Got some trouble codes but I don't believe them

[dptyrob]

I just installed a new set of intake manifold gaskets on the 350 in my 98 GMC Suburban a few weeks ago. A few days ago it started intermittently stumbling, dying at idle, and the CEL came on. It feels a great deal to me like what I have experienced with air bypass valves and EGR valves when they stick. I would drive it for a bit, the stumbling would stop, and the CEL would go on. It came on this morning while I was getting ready to head home from a trip from out of town and has run kinda crappy ever since. On the way home I stopped and had he codes pulled, one of which was 101 and the other 108, problems with the MAF and MAP. I bought some cleaner for the MAF, pulled it off, and brought it inside. I haven't cleaned it yet, as it looks pretty clean already. I replaced the MAP sensor when I did the intake manifuld too. Just thought I'd bounce this off of you guys and see what you think.

Thanks

Jim

[murdog94]

Id clean the MAF, and take a look at the MAP.. But it seems to me that your IAC needs a good cleaning... I think you are on the right track... You might also have a vaccume leak.. Did you replace the upper intake seal when you had the motor appart??

[dptyrob]

Id clean the MAF, and take a look at the MAP.. But it seems to me that your IAC needs a good cleaning... I think you are on the right track... You might also have a vaccume leak.. Did you replace the upper intake seal when you had the motor appart??

No, didn't replace the upper intake seal. I have the one that came with the set around here somewhere though.

[murdog94]

Seems to me that you are running a touch on the lean side and since you might have an air leak that is causing the computer to pick those two sensors since the MAF is as i am pretty sure you know for how much air is coming onto the engine, and the MAP is to make sure the vaccum is correct and altitude etc..
I try a bit of starting fluid around the motor looking for a vaccum leak as well. Just be super careful around the EGR tube since that will ignite anytype of fluid very easily...

[dptyrob]

Just pulled the IACV and found a hump of sorts, made out of carbon, built up on the end. Brushed that off and put it back in and it seems to be starting and idling much better, but the CEL is still on. Is this something where if I solved the problem that it will just take x amount of starts for the light to go off?

[murdog94]

Reset the computer... You simply need to disconnect the battery and touch the positive and negative terminals (the cable ends not trying to talk down to you just some people have tried the other way) for 30 seconds and reconnect..

[dptyrob]

This one has 2 batteries. Disconnect both and touch ends on one pair?

[murdog94]

THat should do it... How did you swing a dual battery set up in a Gas susburban???

[dptyrob]

THat should do it... How did you swing a dual battery set up in a Gas susburban???

Dunno. That's just the way it was when I got it.

I went back out a little while ago to move and unhook my trailer and the light is off now. Yay!!!

[murdog94]

Glad to hear.. Should be good to go then.. Just keep an eye on the IAC since they can go bad as well.