OK Techs...mechanics......I got one for ya.....it's driving me crazy!!

[Grocery Getter]

So.....I've been chasing the ghost in the machine for about a month now. Started with CEL on and rich code w/MAF......cleaned MAF ect...ect...then went to rich code fuel comp sensor......not wanting to buy that part I changed fuel filter and got a new gas cap and the CEL went off for over a week. Now every time I fill up I get the CEL and the fuel comp low charge/voltage code or something along those lines....it comes and goes off usually between 3/4-1/2 tank....and stays off until I fill up again, and no....I am not toping off.

Any ideas????

 

[Grocery Getter]

Nada...nobody......not a one of y'al have ever seen this happen.......come on fellas'

help a brutha out

 

[Rivieraracing]

Wish I could but haven't encountered that problem yet!! I'm sure someone will chime in here eventually!!

 

[digitalfiend]

I know this is an old thread...but did you ever solve this?

 

[ccapehartusarmyINF.(ret)]

what is the code or codes they start witha p

 

[digitalfiend]

I was getting P171 and P174 on my 2004 Tahoe (5.3). The codes would occur at the same time and they started a couple weeks ago, which was the same time that a cold front came through. I just finished swapping out the intake manifold gaskets with the new improved intake gaskets. The codes haven't come back yet.

As an aside, my Tahoe used to idle a little rough before I replaced the gaskets. It was only a slightly rough idle, but enough for me to notice. Also , when I graphed out the front O2 sensor voltages I noticed a tendency for the truck to consistently run a little lean. With the new gaskets the truck idles VERY smooth. The lean condition on the O2's seems to have improved as well.

We're due some cold weather in the next week here in San Antonio and I'll keep an eye out for any new codes, then update this thread with how everything sorts out.

 

[digitalfiend]

I realized I never followed up with this...so I figured that I'd post an update. Changing out the gaskets fixed this problem for me. If you do this repair then I recommend you spend the extra money and get the more expensive gaskets. They cost more, but they look to be vastly improved over the original gaskets. Just ask your parts store to show you both the gaskets side-by-side and you'll see what I'm talking about.