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Car Won't Idle Until Hot

C

CNorell145

New member
Alright guys, this is my last problem I a having with the 2000 GTP. The car will not idle at all without giving it gas when cold. Doesn't even try to catch itself, it just dies immediately. When up to temp however, it takes about 10-15 seconds to catch itself on startup, then it will idle perfectly. While catching itself it revs between 500-1500 RPM or so, slowly getting closer to the target RPM until it evens out. The car pulls just fine and once it gets idling, it is fine until I shut it off again. Then the same process with trying to catch itself. I have checked for vacuum leaks, replaced the IAC valve and the MAF. I have the throttle body off a 1997-1999 Cadillac DeVille, so thats the MAF and IAC I got.

I was thinking fuel pressure regulator and/or the fuel filter, but wouldn't I also have problems while accelerating if that were the case?
 


is all this since the tb and maf change? cause that would need a tune. no tune and im surprised it even runs.

or your tb is filthy dirty.
 
The TB has been the same since I got the car, just got a working MAF, and I had someone tune it just yesterday, we got it running perfectly except for the idle... Now I'm not sure which tables he changed exactly, I want to say he just gave it timing and made sure the fuel trims were sound. Not sure what he did for the idle... I believe that he tried to up the fueling for the lower Hz on the MAF, but it never really read below 3150 or so...
 
What I don't understand is why it would not even try to correct itself when cold, and it can catch itself when hot, but it takes 10-15 seconds. It's all just really strange.
 
ive read something about N* tb needing a hole drilled in it somewhere. no idea where tho.

the maf, what code did it set? and i can only assume you cleared it cause most pcm's wont take a flash with a set code present. but has the code come back?
 


it may take a few days to re set it if its not the maf. how are the wires done for the new mafs? one of them adapter harnesses or was it cut and spliced in.

if you have a harness for it double check your stock maf pig tail wires for damage. if you see bare wire or cracks the pig tail is bad.

if it was spliced in i hope it was soldered and shrink tube over it.
 
No splicing or anything was necessary, it used the factory plug. The TB is off a 97 Cadillac Deville. And there is no damage to any of the wires.
 
Yes, it's a N* TB. This is the TB that came with the car when I got it. I have thought about getting a different one, but this one seems to work just fine... except for the idle issue. But if it was the TB, I would think the car would never run properly. What I need to figure out is everything that goes into the initial startup of the car. IAC and MAF should be fine. From what I have heard, the O2 sensor doesn't kick in until the system goes into a closed loop. So I'm not sure what else to check.
 
did it idle like this before the tune when the maf was bad? im guessing it came with a bad maf too?

you spray carb cleaner at the vac lines and tb spacer and blower base and injectors yet to see if its a vac leak?
 


It has idled like this since I got it, however it is worse now, since it dies when cold. I sprayed carb cleaner everywhere, couldn't find a single leak...
 
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