Low MPG stumbles @ idle Code P0014

[xx_gearhead_xx]

I'm going to address two issues I found while replacing my CPAS. First alittle back story. Over the course of the past couple months I've been having trouble with low gas mileage. I've done the usual maintenance, clean TB, checked spark plugs, etc. All in good condition. Had new tires put on (due to being worn), checked tire pressure, nothing, still below average. Then out of the blue I get code P0014 and intermittent idle stumbles, it never stalled but came close. So after cleaning the CPAS with no change in the performance, I buy a new one.

View attachment 30391

This was picked up at the local NAPA for about $88 (Delphi PN SL10064) It's stated as being the original OEM brand for the TB as I couldn't find an AC Delco one which I found out they don't make. (I'm sure I could've found it cheaper online, but speed was key here as it's my DD) It worked as advertised and as plus ( not sure of other the other brands, maybe someone can chime in) it came with springs mounted over the oil screens to prevent them from falling out, a known issue with stock CPAS. Highlighted in the pic below

View attachment 30392

While changing out the CPAS I remember other members having problems with loose manifold bolts. So I stop and think, at 160K+ it might be worth a look. I break out the trusty torque wrench and with some finesse manage to get a hold of a manifold bolt.

I had the torque set at 55in lbs, thinking if it's loose, I might have a better idea of about just how bad it is. 3/4 of a turn later and I get it tight, then about 1/2 turn to torque. Long story short, after removing the alternator and getting the PCM mount outta the way I torqued all the bolts back down. (Except for the one against the firewall as it's a pita to get to so I used a combination of extensions and swivel to tighten it by hand). Buttoned everything back up and no more code for the CPAS and better pickup at light throttle. The idle was back to normal and even the sound of the engine was smoother. I was shocked to find that all of my manifold bolts were loose and not even close to proper torque. I'm usually pretty good about maintenance but that bit definitely slipped my mind. I can only imagine how long they have been loose. Not sure of what a good interval would be to check those bolts or if just putting some locktite on there would solve it but I know now I def need to keep better track of it.

I just put a full tank of gas in so I will check the mileage again in a couple days. My current best is 18mpg highway 70mph and under, I used to touch 20-21mpg. I'm curious to see just how much these two issues contributed to that or if I still have another issue. Hope this helps other ppl think twice about waiting till later to check those manifold bolts. Also, if someone else has bought a CPAS recently I'd like to know what brand and if it came with the oil screen springs as well. Thanks again to the community and I hope this helps other ppl out as well.

 

[gmcman]

I was averaging what you were which was under the norm from what I would generally see. After replacing the thermostat, temp sensor, and the upstream O2 sensor the MPG came back. The O2 sensor made a noticeable difference.

Do you have a scan tool and can you monitor the coolant temp? If the motor cannot achieve 195 deg and maintain it then I would change out the stat and sensor.

Generally when the stat/sensor begin to fail, the temp needle begins to stay at one tick mark under at it's highest and generally 2 ticks to the left. Mine moves from straight up to 1 tick to the left but generally straight up. When the coolant is not up to temp, the ECM adds more fuel thinking it's still warming up.

I say change those if you haven't yet.

 

[Jtyler77]

I got the same thing with the springs from gmpartsdirect #12615873. I didnt know what to think when I seen it, but no issues....

 

[xx_gearhead_xx]

@ gmcman <> I've recently changed the water pump when it failed and the thermostat as well since I was there. So I don't think that should be an issue. I'm thinking more along the lines of the O2 sensor sense the last time I changed it was over 50K and it was an advance auto special. I had forgotten I didn't get a GM sensor, I'll definitely have to look into that when I get a chance.

@JTYLER77 <> Thanks for the heads up!

 

[moogotzskillz2]

I got the same thing with the springs from gmpartsdirect #12615873. I didnt know what to think when I seen it, but no issues....

There on sale for $34 is this the right part?


Is it also called Engine camshaft sprocket?

Thanks

 

[Jtyler77]

There on sale for $34 is this the right part?


Is it also called Engine camshaft sprocket?

Thanks

Yep, thats it

 

[xx_gearhead_xx]

I finally got around to changing out the O2 sensor, needless to say I had the old style sensor installed. It was an ACDelco part but apparently the older style. I did notice a difference in take off and idle once it was warmed up but maybe that was just me. Having changed nothing else besides the O2 sensor and being cooler outside I'm curious to see if I get a noticeable difference in MPG.


View attachment 18655

 

[CaptainXL]

being cooler outside I'm curious to see if I get a noticeable difference in MPG.

Winter blend gas a cold weather make for horrible gas mileage. Just so you know. The summer time when temps are around 70F are the ideal time to record mpg's.

And as far as oxygen sensors go you should only use ACDelco. They have a specific heater resistance figure which is know to work better.

 

[xx_gearhead_xx]

you should only use ACDelco. .

As far as parts go, the Denso sensor was listed as OE part for NAPA since they didn't carry the ACDelco one. So I don't believe there should be an issue there. I tried pulling up a p/n for the ACDelco one but they still had pictures of the old style sensor. Does anyone have a p/n for the new style ACDelco sensor?

 

[Inert_Static]

I had the torque set at 55in lbs, thinking if it's loose, I might have a better idea of about just how bad it is. 3/4 of a turn later and I get it tight, then about 1/2 turn to torque. Long story short, after removing the alternator and getting the PCM mount outta the way I torqued all the bolts back down.

Just a quick question. Is that the correct torque setting ? I don't have the service manual... And this makes me want to check my manifold bolts....

 

[xx_gearhead_xx]

Just a quick question. Is that the correct torque setting ? I don't have the service manual... And this makes me want to check my manifold bolts....

No, I did that as a test, the GM repair manual calls for 12ft.lbs or 144in.lbs for intake manifold bolts. I believe the Haynes manual says 89in.lbs but I would go with the GM.

 

[gmcman]

No, I did that as a test, the GM repair manual calls for 12ft.lbs or 144in.lbs for intake manifold bolts. I believe the Haynes manual says 89in.lbs but I would go with the GM.

Triple check those torque values, 144 seems high. Make sure its the 4.2 and not the 4.3.

Quadruple check. I'm just leaning on the side of caution since 89 inch pounds is a widely used value with the 4.2

 

[Wooluf1952]

Triple check those torque values, 144 seems high. Make sure its the 4.2 and not the 4.3.

Quadruple check. I'm just leaning on the side of caution since 89 inch pounds is a widely used value with the 4.2

I agree. My 2003 Service Manual calls for 89 in. lbs.

 

[CaptainXL]

It's 89 in lbs according to Alldata. But if the bolts are really loose it would be a good idea to completely remove the intake manifold to check the gasket to see if there isn't any gunk keeping you from properly torqueing the bolts back down. Just tightening them down seems useless without a good inspection.

 

[dla442]

I'm going to address two issues I found while replacing my CPAS. First alittle back story. Over the course of the past couple months I've been having trouble with low gas mileage. I've done the usual maintenance, clean TB, checked spark plugs, etc. All in good condition. Had new tires put on (due to being worn), checked tire pressure, nothing, still below average. Then out of the blue I get code P0014 and intermittent idle stumbles, it never stalled but came close. So after cleaning the CPAS with no change in the performance, I buy a new one.

View attachment 17186

This was picked up at the local NAPA for about $88 (Delphi PN SL10064) It's stated as being the original OEM brand for the TB as I couldn't find an AC Delco one which I found out they don't make. (I'm sure I could've found it cheaper online, but speed was key here as it's my DD) It worked as advertised and as plus ( not sure of other the other brands, maybe someone can chime in) it came with springs mounted over the oil screens to prevent them from falling out, a known issue with stock CPAS. Highlighted in the pic below

View attachment 17187

While changing out the CPAS I remember other members having problems with loose manifold bolts. So I stop and think, at 160K+ it might be worth a look. I break out the trusty torque wrench and with some finesse manage to get a hold of a manifold bolt.

I had the torque set at 55in lbs, thinking if it's loose, I might have a better idea of about just how bad it is. 3/4 of a turn later and I get it tight, then about 1/2 turn to torque. Long story short, after removing the alternator and getting the PCM mount outta the way I torqued all the bolts back down. (Except for the one against the firewall as it's a pita to get to so I used a combination of extensions and swivel to tighten it by hand). Buttoned everything back up and no more code for the CPAS and better pickup at light throttle. The idle was back to normal and even the sound of the engine was smoother. I was shocked to find that all of my manifold bolts were loose and not even close to proper torque. I'm usually pretty good about maintenance but that bit definitely slipped my mind. I can only imagine how long they have been loose. Not sure of what a good interval would be to check those bolts or if just putting some locktite on there would solve it but I know now I def need to keep better track of it.

I just put a full tank of gas in so I will check the mileage again in a couple days. My current best is 18mpg highway 70mph and under, I used to touch 20-21mpg. I'm curious to see just how much these two issues contributed to that or if I still have another issue. Hope this helps other ppl think twice about waiting till later to check those manifold bolts. Also, if someone else has bought a CPAS recently I'd like to know what brand and if it came with the oil screen springs as well. Thanks again to the community and I hope this helps other ppl out as well.

Your intake bolts were loose? Wow

 

[dla442]

As far as parts go, the Denso sensor was listed as OE part for NAPA since they didn't carry the ACDelco one. So I don't believe there should be an issue there. I tried pulling up a p/n for the ACDelco one but they still had pictures of the old style sensor. Does anyone have a p/n for the new style ACDelco sensor?

Hopefully the pic attatches. The new one on the bottom and the old one on the top I took out as of a few days ago. Upstream sensor in the manifold. 62.00 here in Grand Rapids.

 

[xx_gearhead_xx]

.. I'm just leaning on the side of caution since 89 inch pounds is a widely used value with the 4.2

I did see that number and the manual I checked had 12ftlbs. Though, looking closer it says the picture is from a GM manual. So it seems the torque value was written incorrectly in that procedure by Mitchell Repair.

Hopefully the pic attatches. The new one on the bottom and the old one on the top I took out as of a few days ago. Upstream sensor in the manifold. 62.00 here in Grand Rapids.

Thanks for the heads up! I checked the P/N on the box you took a pic of but it says it does not work with an 06 TB. It appears on ACDelco's website P/N 213-3539 is for 06 and up vehicles and P/N 213-1698 for 05 and older. Does anyone know what the difference might be in the sensors for the 06 and newer TB's?

 

[Nmeraz08]

I recently did an oil change about 2 weeks ago to my 2002 Trailblazer LTZ. Today the Service engine light came on and I got code p0014. I'm willing to work on my truck to learn how to fix the issue but at the same time I noticed that I get a low MPG. What can I do to fix these issues?

 

[IllogicTC]

I recently did an oil change about 2 weeks ago to my 2002 Trailblazer LTZ. Today the Service engine light came on and I got code p0014. I'm willing to work on my truck to learn how to fix the issue but at the same time I noticed that I get a low MPG. What can I do to fix these issues?

p0014 involves your CPAS. There's an article here that shows how to maintain the CPAS system, along with some discussion further down the page with a couple of other issues. I wouldn't bust out the wrench set just yet without seeing what other members have to say, but the guide linked above may be your ticket out (and a lot cheaper than actual replacement, though replacement I would imagine follows very similar instructions).

In the meantime while waiting for other members, what brand oil did you use? Most people around here suggest Mobil 1 Synthetic, if I recall correctly. It'd be a good place to start if we knew the brand, viscosity, and if you did the filter while you were under there. I know there's some amount of brand bias, happens anywhere, but there are indeed some brands that just don't hold up to snuff.

 

[Nmeraz08]

p0014 involves your CPAS. There's an article here that shows how to maintain the CPAS system, along with some discussion further down the page with a couple of other issues. I wouldn't bust out the wrench set just yet without seeing what other members have to say, but the guide linked above may be your ticket out (and a lot cheaper than actual replacement, though replacement I would imagine follows very similar instructions).

In the meantime while waiting for other members, what brand oil did you use? Most people around here suggest Mobil 1 Synthetic, if I recall correctly. It'd be a good place to start if we knew the brand, viscosity, and if you did the filter while you were under there. I know there's some amount of brand bias, happens anywhere, but there are indeed some brands that just don't hold up to snuff.

The truck currently has 139350 miles. I used Quakerstate oil 10W-30 with an STP brand oil filter change. I bought the TB in December of 2013 and had it in the garage. Through that time in the garage I started it in the morning everyday for 10 min. I took it out of the garage this past Friday with no problems. I drove it to get insurance and plated and everything checked out good. I made another stop that same day to get groceries and as I started the truck it stalled after 10 seconds. I gave it a little gas and seemed to be under control. After this day it has never stalled. However, today after I got out of school I drove home and like 15 min later the SES light came on. Later on the day I went to Autozone and got a diagnosis and got code p0014.

 

[CaptainXL]

Assume the vehicle and engine were abused maintenance wise.

I would start with getting a new CPAS. Forget about cleaning it at your mileage. It has more than likely never been replaced.

Also start using 5w-30 and a good oil filter.

The fine oil passages used for the CPAS and variable cam timing are susceptible to a general lack of maintenance and age.

 

[Nmeraz08]

Assume the vehicle and engine were abused maintenance wise.

I would start with getting a new CPAS. Forget about cleaning it at your mileage. It has more than likely never been replaced.

Also start using 5w-30 and a good oil filter.

The fine oil passages used for the CPAS and variable cam timing are susceptible to a general lack of maintenance and age.

Most likely because I seen that they did the tune up June of last year. But I'm still worried about my low MPG because it wasn't like that when I got it.

 

[CaptainXL]

I seen that they did the tune up June of last year.

What type of work was done?

 

[Nmeraz08]

What type of work was done?

The plugs oil change and air filter.

 

[IllogicTC]

Switch as soon as possible to 5W30, as suggested by the manual and the cap itself that was removed to add oil.

The higher the viscosity number, the "thicker" the fluid. For oils with a "W," it means there's two viscosity grades here. The first number is the "cold" viscosity, and the second is the "warm" viscosity, measured at 100 degrees celsius. So when the oil is all warmed up, it pretty much performs like SAE 30. But when you're first starting a cold engine, the lower the first number the thinner the oil, which means it can get worked up through the system more quickly (which in turn will get it heated and thickened up to provide a proper protective layer).

From a quick reading around the CPAS is especially sensitive to oil-related things, so running an oil that takes longer to get initial flow top-side where the unit is, especially in the weather we're having lately, could be all it needs to get angry.

 

[Nmeraz08]

Switch as soon as possible to 5W317845-18 suggested by the manual and the cap itself that was removed to add oil.

The higher the viscosity number, the "thicker" the fluid. For oils with a "W," it means there's two viscosity grades here. The first number is the "cold" viscosity, and the second is the "warm" viscosity, measured at 100 degrees celsius. So when the oil is all warmed up, it pretty much performs like SAE 30. But when you're first starting a cold engine, the lower the first number the thinner the oil, which means it can get worked up through the system more quickly (which in turn will get it heated and thickened up to provide a proper protective layer).

From a quick reading around the CPAS is especially sensitive to oil-related things, so running an oil that takes longer to get initial flow top-side where the unit is, especially in the weather we're having lately, could be all it needs to get angry.

I got you. Another question I get low MPG. I used to get 17-18 MPG. ..now its more like 8-9 MPG.

 

[IllogicTC]

I got you. Another question I get low MPG. I used to get 17-18 MPG. ..now its more like 8-9 MPG.

It's extremely possible that the issue stems from your CPAS issue. Clean/repair/replace, whatever is needed, and then see if it improves.

 

[Nmeraz08]

Need a couple suggestions as to which spark plugs to use on my blazer for better performance because I want to do a complete tune up on it what else should I do to it. So far the following is done the oil change and air filter.

 

[IllogicTC]

Need a couple suggestions as to which spark plugs to use on my blazer for better performance because I want to do a complete tune up on it what else should I do to it. So far the following is done the oil change and air filter.

For spark plugs, use AC Delco #41-103 Iridium. They're the manufacturer-recommended replacements to the platinums they used to use, and the system gets pretty grumpy about having any other brand of plug. They come pre-gapped from the factory, though it doesn't hurt to use a tapered gauge or feeler gauge to ensure the gap is at 0.042" or within 1-2 thousandths (I know there's actually a range specified, but I'm not sure what it is, most plugs it's within 1-2 thousandths), however DO NOT gap the plugs like you would with the ones on an older car, it'll ruin the electrode.

Change all other fluids - this includes transmission fluid and filter, transfer case fluid, front and rear differentials. Front and rear diffs I believe take synthetic 75W-90 oil. Transfer case takes 2 quarts of Auto-Trak II fluid, which can be had at the local dealer or on Summit (and maybe some other retailers). DO NOT USE ANY OTHER FLUID except the Auto-Trak. Dropping the transmission pan (or if you're lucky, having the plug on there to drain it first) will remove about 5 quarts of fluid, replace with the appropriate fluid. You can also do this multiple times to do a "semi-flush" if you feel the need, but it'd get expensive quick.

If you don't run a brand of fuel that's listed as Top-Tier (toptiergas.com shows all brands officially designated), get a bottle of Techron, it's expensive but your motor will thank you later. It's the only additive I would suggest as it's been proven through people using Chevron gas in their TBs no problem.

Some people dig into doing Seafoam through the motor or some such, I've never done it so I have no personal experience on how much it can improve things.

Earlier model years have a fuel filter that's external to the fuel tank, consider changing that, too.

There are likely things which I am missing. I'm sure this is a no-brainer, but record the mileage for every service you perform, not only for your own records but when matched with receipts can provide a pseudo-record for the next person if you decide to sell, which gives peace of mind (and eases the sale!).

 

[CaptainXL]

What type of work was done?

The plugs oil change and air filter.

Need a couple suggestions as to which spark plugs to use on my blazer.

??? You said the plugs were changed last year. They are good for 100K miles. Don't mess with them unless you want to inspect them or you did 100k miles this past year.

DO NOT USE ANY OTHER FLUID except the Auto-Trak.

There are a couple other GM approved transfer case fluids besides AT2. Royal Purple makes one and some other I can't remember.

 

[IllogicTC]

There are a couple other GM approved transfer case fluids besides AT2. Royal Purple makes one and some other I can't remember.

Just going with the general consensus, the TC is pretty touchy about it especially thanks to the clutch pack. Can't go wrong with what it likely came off the factory line with!

 

[CaptainXL]

the TC is pretty touchy about it especially thanks to the clutch pack. Can't go wrong with what it likely came off the factory line with!

I have read about how they commonly fail. Using another approved fluid besides Auto Trak 2 is not one of them.

By the way you can do better. The Royal Purple is supposed to be better.

 

[HARDTRAILZ]

There are a couple other GM approved transfer case fluids besides AT2. Royal Purple makes one and some other I can't remember.

You and your bullshit.

Autotrak II is the only recommended fluid for a reason.. Royal Purple is not better. The Syncromax from Royal Purple is claimed by Royal Purple to be a substitute, but can't find comfirmation that it is or that it works long-term.

Amsoil gave up trying to reverse engineer AutoTrak II cause they could not match it.

 

[IllogicTC]

I have read about how they commonly fail. Using another approved fluid besides Auto Trak 2 is not one of them.

By the way you can do better. The Royal Purple is supposed to be better.

I don't believe it. I looked at the products available directly from the website: Transfer Case - 4 Wheel Drive | Royal Purple Industrial

Their three options are:

Max ATF fluid. Automatic transmission fluid isn't Auto-Trak II. If it were good enough, GM likely would have just put ATF in there in the first place. Some Ford TCs take Mercon-compatible fluids, the ATF would be fine for that, but this isn't a Ford. Some GMs with manual cases take Dexron-compliant. Our A4WD cases require special friction modifiers thanks to the clutch pack, that isn't offered in the specs for ATF.

MAX-GEAR. Specifically says it's for differentials and manual transmissions. The pretty picture shown is a common weight at 75W-90, other viscosity options are available. Does anyone even know the weight for AT II?

Royal Purple Motor Oil. Yeah, lemme just load that right up.

 

[CaptainXL]

Gentleman please let this not turn into a flame thread.

I researched this years ago so I know what I am talking about. Take a look at this cross reference.

http://royalpurpleconsumer.com/wp-content/uploads/Transmission_Lubricant_Cross_Reference_Chart.pdf

Scroll down to the GM section and you will find that Synchromax is a recommended substitute.

On top of this there are many positive reviews from other GM truck forums that utilize a transfer case using this fluid.

Also Royal Purple knows their formulation is better and they recommend it over AT2. If they were the least bit unsure they wouldn't be so confident.

 

[IllogicTC]

I wouldn't buy into the "confidence because guaranteed better," it's up to the consumer and not the producer to decide that. After all, they're just selling a product and may or may not be accurate in their claims of superior performance - however, the consumer CAN discern for themselves. If we could just trust ads at face value, we wouldn't have so many review websites in existence for every type of thing.

It does say it's compatible with all types of friction material. Kind of strange they didn't list it in their transfer case section. Apparently users of the NVG 246 (also with A4WD functionality) have reported it works for theirs, not sure if that's a guarantee the 226 or 126 would also accept it. But I know what we all recommend on here, and that information isn't all just "the manual doth say, thus shall we do!," people try substitutes (whether cheaper, or more expensive for performance) for fluids all the time and there's probably a reason AT2 has stuck around as the one parroted by all the offroaders around here.

That and I can buy AT2 at $8 a quart, as compared to RP at $15+, and not technically be "cheaping out," which is always nice

 

[CaptainXL]

Autotrak II is the only recommended fluid for a reason.. Royal Purple is not better.

Auto Trak 2 fluid is a formulation of a semi synthetic transmission fluid dyed blue.

The reason Auto Trak 2 has always been recommended by GM is because synthetic automatic transmission fluid was not prevalent during it's introduction. It just stuck and they keep making it. Hell, people use Dexron VI in their transfer cases all the time now and it works great.

 

[IllogicTC]

Auto Trak 2 fluid is a formulation of a semi synthetic transmission fluid dyed blue.

The reason Auto Trak 2 has always been recommended by GM is because synthetic automatic transmission fluid was not prevalent during it's introduction. It just stuck and they keep making it. Hell, people use Dexron VI in their transfer cases all the time now and it works great.

It also kind of has those friction modifiers for the clutch pack...

I mean, if it's confirmed compatible, I guess it's up to the dude up there to decide which he wants to pour in, but I know I'd stick with AT2, as would a bunch of others. Everyone's own vehicle is subject to their own decisions on fluid purchases in the end and none of us can change that

 

[CaptainXL]

It also kind of has those friction modifiers for the clutch pack...

..and what do you think is in synthetic automatic trans fluid? Don't just take my word for it. Read up. Tons of people on the internet have switched from Auto Trak II to using fully synthetic fluids like Mobile 1, Royal Purple and Amsoil, Dexron VI. Other shit works, not just the AT2.

Years ago GM had a hard time with the NP246 chucking parts and wear problems. They went through a couple revisions of the fluid before they came up with...tada Auto Trak II! Guess what the revisions were about? The percentage of synthetic stock in the fluid. That's all. Nothing special. But use whatever you want.

Just remember Auto Trak II is old technology. Modern full synthetics are much more adept at protecting the transfer case.

 

[HARDTRAILZ]

I can always count on captainxl's ignorance for a laugh.

Thanks buddy!