P0442 fix may affect alot of leaks and idle problems.......

[TB2004]

So a several weeks ago temps dropped into 20's here and the engine would idle rough, almost stall and the service engine light came on. Last year when it got cold same code came on and it was the filler neck hose at the tank was completey loose. Tightened it up and was good to go. So my first thought was filler neck crack at the tank. Couldn't find anything in evap system and was getting ready to try and get a smoke test done. $115.00 at dealer, but they would wave it if I had them do the repair. Local shop was $89.00 plus repair. After researching how to make my own smoke machine, I suddenly remembered the hose at front of the air box seemed slightly loose when we cleaned the throttle body a month earlier. I took a chance and ordered it through the dealer, $17.00, replaced it and reset codes. Looking at the old one where it connected to the valve cover, there were a few verticle cracks where it connected to the valve cover. Sure enough that allowed air to pass when it was cold, which effected the idle and then kicked the code. New hose is tight on the nipples and for last 2 weeks plus all is well, runs better each day, also we've gotten a few mpg better around town and highway. The dealer said it was the pcv hose, didn't find a pcv valve tho. Hope this helps someone with their TB..... Merry Christmas Everyone!

Here's a pic 4.2L engine:

 

[linneje]

If you have the 4.2L engine, there is no PCV - the 5.3 does have one, though. However, there is a vent hose to ventilate the crankcase, perhaps that is what the dealer meant.

 

[TB2004]

Yes I forgot to put that in, 4.2L engine, trying to get a pic uploaded to show. Thanks...

 

[jpimp]

Good info!
Do you have the part number for future reference?

 

[TB2004]

No I don't have the part number, dealer said pcv hose. We ordered off the schematic over the phone and it worked out.

 

[cart7881]

Part Number 24577310. Dealer purchase will set you back $15.30. http://parts.nalleygmc.com/showAssembly.aspx?ukey_product=2999067&ukey_assembly=436453&ukey_make=0&ukey_model=0&ukey_driveline=0&ukey_trimlevel=0&modelYear=0

 

[Mounce]

Part Number 24577310. Dealer purchase will set you back $15.30. http://parts.nalleygmc.com/showAssembly.aspx?ukey_product=2999067&ukey_assembly=436453&ukey_make=0&ukey_model=0&ukey_driveline=0&ukey_trimlevel=0&modelYear=0

Good find.

 

[Wooluf1952]

Just to clarify; The 4.2 has a PCV system. It does not have a PCV Valve. That's the main reason the T-body gets so dirty.

 

[TB2004]

You are correct!

 

[IllogicTC]

Just to clarify; The 4.2 has a PCV system. It does not have a PCV Valve. That's the main reason the T-body gets so dirty.

Yep, though technically it's because of the side that goes into the intake manifold (that's why it gets all over the backside).

Speaking of that, I found a Dorman replacement intake manifold that replaces that hose that runs up the center with an integrated tube. The dude also explains other improvements they made to the OEM manifold, interesting stuff.

[media]https://www.youtube.com/watch?v=S_gwSM1J1aU[/media]

 

[TB2004]

A quick update! This must have been leaking a long time but not kicking a code. There used to be a lag in accelleration also when merging onto the freeway it would always downshift. Now no lag and much better with little to no downshifting.... Hope this helps.

 

[sunliner]

very cool. I fought a 0442/0455 issue myself (in my case it seems to be from crumbling hose to the purge solenoid. fixing that cleared the way for a recurrent P0171.
Just curious, how did you make your own smoke machine? I might need to look into this...

 

[TB2004]

Sorry about the long delay in the reply, health problems have kept us busy since new years. I didn't have to make the smoke machine yet. When I had the PO171 it was the upstream O2 sensor. This info may help you out. Once again sorry for the long delay in responding....

http://www.obd-codes.com/p0171

 

[Gerbil21]

do you have any pics of the cracks in the old hose?

 

[TB2004]

do you have any pics of the cracks in the old hose?

No but if you look up the hose you will see cracks that run up into the hose where it is supposed to seal around the connections.

 

[Gerbil21]

No but if you look up the hose you will see cracks the run up into the hose where it is supposed to seal around the connections.

As you saying to look at mines to check? Sorry if I misunderstood, but yes my hose has cracks on it too I just didn't think it made much of a difference until i saw this thread. Just wanted to see a pic to compare but I'll just replace it when I get a cai lol

 

[TB2004]

Yea replace if any cracks, helped mine alot. Sorry about long delay.

 

[Sparky]

I have no codes but I've felt it has been "down" on power a bit. I wouldn't have thought anything of that hose but I wonder if it is at all related. Not going to bother with it now since I'm (hopefully) getting a replacement truck this year, but that's interesting. Also annoying if that simple hose is what was causing it!

I wonder about that Dorman manifold. Stock has the hose running to before the throttle body. That manifold has it run after the throttle body. Wonder what (if any) difference that makes

 

[TB2004]

Congrats on the new truck. I know it really helped out mine tho...