'01 Yukon Throttle body cleaned, low idle & quits now

[Tonyrodz]

Dealers or parts stores--in my experience--don't sell the iacs separately. Dealers will only sell the complete throttle body assemblies, which I don't understand. My cost starts at $300. I'm having the same issue with my 4.8 when it's cold. Once it warms up it's fine.

 

[Doubeleive]

Dealers or parts stores--in my experience--don't sell the iacs separately. Dealers will only sell the complete throttle body assemblies, which I don't understand. My cost starts at $300. I'm having the same issue with my 4.8 when it's cold. Once it warms up it's fine.

Ya it's been a while since I went thru that deal, probably explains why I just ended up getting the same one from the junkyard and couldn't find a oem one online that wasn't some completely ridiculous price

 

[bill9000]

So, the IAC valve was a slightly different length, never would have been noticable if not looking for it, but maybe 1/32nd longer.

Cleaned it put the old one back, and now it does not immediately quit when started which is a great thing.

However, the original problem still exists... just random roughness at idle, almost sound like a miss, very sporadic... doesnt seem to quit, but sort of sounds like it might. Doesn't instill a lot of confidence for not getting stranded in a snowstorm.
Not sure now... new throttle position sensor, disconnected battery for 30 mins, put the old IAC back in... throttle body is very clean... still doesn't idle quite right. (it also has brand new spark plugs and wires)

 

[Tonyrodz]

MAP sensor maybe?

 

[HiHoeSilver]

have you cleaned the MAF?

 

[bill9000]

have you cleaned the MAF?

I did. with the MAF cleaner spray.

 

[bill9000]

I cleaned the MAF (by spraying it with the cleaner that was for that) - is it possible that's not good enough? would replacing the MAF possibly fix a sporadic miss sound at idle?

in other words, CAN the MAF cause that type of symptom?

 

[Doubeleive]

when my iac went bad it would just idle really low up/down, still smooth firing just unstable idle, if you don't have any misfire I would lean towards the maf like mentioned above, how many miles? my opinion on the maf sensors is they tend to start taking a crap around 160k and they can cause a variety of problems including weird shifting. could be a combination of the iac and maf sometimes you have to shotgun repairs on these things because several things can be screwy. with the other iac on there did it idle smooth and just die? or was the same problem present also?

 

[bill9000]

when my iac went bad it would just idle really low up/down, still smooth firing just unstable idle, if you don't have any misfire I would lean towards the maf like mentioned above, how many miles? my opinion on the maf sensors is they tend to start taking a crap around 160k and they can cause a variety of problems including weird shifting. could be a combination of the iac and maf sometimes you have to shotgun repairs on these things because several things can be screwy. with the other iac on there did it idle smooth and just die? or was the same problem present also?

no misfire codes or anything, it sound like its missing sporadically, and just a low idle.

it has 152,000 miles, and I just don't trust it anymore... too many things going wrong. But I'm stuck for the winter, so I have no choice but to try and limp it through.

When I had the other (new) IAC, I want to say is SEEMED smoother, but it would just start and immediately quit. you'd have to hold the gas up to get it to stay running, then once it was running, it seemed to sorta stay running, but it would just dip really low idle aver revving down, and almost quit.
I don't really recall hearing the weird miss type sound, but I can't be certain.

 

[Doubeleive]

is there a junk yard around you? if so you can probably pick up a used maf for around $30-35, a new delphi on rockauto is $85.00 there are some cheaper aftermarket ones but I wouldn't recommend them.