p0300

[dwzook]

Who's had p0300 and what was the problem, or how did you diagnose further? I read a service bulletin stating the injectors have problems.

 

[djthumper]

It is is random cylinders having the issue. I would get injector cleaner and reset the code to see if it continues to be random. Mine actually worked it self to be 1 and 2.

 

[KNBlazer]

what I did when I had the P0300, I disconnected each coil one at a time until I found the cylinder that had no change, once I did that, I swapped coils with a different cylinder and finally got a P0302 using the coil from cylinder 1....

 

[JCJARHEAD]

I used a better scan tool to determine that coil packs had gone bad. I had replaced one earlier but that time the code gave a specific cylinder. Long story short, I did the remaining good coils also as it seemed that they were all crapping out in close intervals.

 

[The_Roadie]

There have been quite a few threads (search for P0300 or "random misfires"). If you're above 80K since your last plugs, just change them. The sorts of things that cause random misfires are (sort of statistically in order of reports I remember):

Stale/damaged plugs (swap 'em, they're cheap, use Delco 41-103 only)
Marginal coils (diagnose by swapping or disconnecting one at a time - or take a new one down the line)
Marginal injectors (seafoam treatment or a real cleaning)
Erratic or low compression ( run a compression test - get ready to pay for a head job or gasket)

A lot of it depends on mileage and maintenance history, which everybody could help you more if you'd share that data.

 

[2x1968muscle]

Hello,
just limped home with what turned out to be P0301 code
-swapped out coil number one and i'm back in business.
After reading the posts above I have decided to replace the spark plugs to eliminate that from the cause list.

My question is about the coils. I had one of the stock ones fail in the summer of 2013 and I replaced all 6 with Standard Motor Products coils. Since then I have had 3 of the Standard Motor Coils go bad on me and I have limped home to re-install one of my "spare" Delco coils.
Like many of the other parts on these trucks, should I only be putting Delco coils on this engine? or is there an acceptable quality brand out there that will last more than a year.

Thanks for the help, it's really appreciated.

2003 Trailblazer EXT 4.2 with 148000 kms

 

[KNBlazer]

Hello,
just limped home with what turned out to be P0301 code
-swapped out coil number one and i'm back in business.
After reading the posts above I have decided to replace the spark plugs to eliminate that from the cause list.

My question is about the coils. I had one of the stock ones fail in the summer of 2013 and I replaced all 6 with Standard Motor Products coils. Since then I have had 3 of the Standard Motor Coils go bad on me and I have limped home to re-install one of my "spare" Delco coils.
Like many of the other parts on these trucks, should I only be putting Delco coils on this engine? or is there an acceptable quality brand out there that will last more than a year.

Thanks for the help, it's really appreciated.

2003 Trailblazer EXT 4.2 with 148000 kms

I suggest AcDelco or GM only when it comes to electronics... some members have reported auto zones coils to be delphis, of course who knows if the guts actually fall under Delphi's guidelines....you can buy a set of 6 AcDelcis from ebay for $225.00.... I just bought some last week for $213.00, unfortunately engine took a dump on Monday, so will wait to install them...

Your coils didn't come with a LLW? you could return them and upgrade to maybe Borg Warner..

 

[2x1968muscle]

I suggest AcDelco or GM only when it comes to electronics... some members have reported auto zones coils to be delphis, of course who knows if the guts actually fall under Delphi's guidelines....you can buy a set of 6 AcDelcis from ebay for $225.00.... I just bought some last week for $213.00, unfortunately engine took a dump on Monday, so will wait to install them...

Your coils didn't come with a LLW? you could return them and upgrade to maybe Borg Warner..

Hi and thanks for the suggestion. I might just have a look at Ebay.
Warranty? here in Canada automotive electronics carry at best a 6 month exchange policy unless you have them installed at a shop. Then they will extend the warranty further....but you end up paying 3x or even 4x more for the part cost.
I installed them myself of course, so basically no warranty.
Ebay here I come

**set of 6 on ebay for $219**
no warranty <sigh>

 

[KNBlazer]

here in the states, auto part stores carry lifetime limited warranty....

 

[Mike w]

I had this problem it was p0300 while it was misfiring I unplugged coils one at a time and it was a coil.

 

[Mike w]

Funny thing is the coil would fire until it got up to operating temp. .

 

[Mike w]

Dwzook I have a compression guage I will send to you free of charge if need be anything to help the community

 

[Ev Ritter]

My 2002 LTZ threw a p0301 this morning following 2 weeks on the new Bosch Iridums replacing the oem ACDelco 41-103 Iridium plugs. The coil pak from cylinder #1 had less than 7,000 miles on it ! Go figure ! I replaced two others last year from AIP Electronics. They carry a 90 day warranty. {@ $40.00 each they are a good buy, compared to the factory Delphis}which seem more expensive.and are supposed to be oem specs.
I like the Bosch {4514} HGR8MQIO 4 Platinum IR Fusion Spark Plugs
plugs with the 4 ground points on them. They fire brillently.