Just when my car is cold(sitting over night/more than 4 hours) it will start but goes down to like 500rpm, sounds like its gonna die, then revs up to 1500rpm. This process repeats for a few minutes and gradually gets less sparatic. Anyone have any idea what it could be. BTW it idles fine whn first started but it is warmed up.
Thanks
-Mark

 

ttt

 

be sure to check for vacuum leaks. it sounds like a vacuum leak somewhere. guys around here use carb cleaner and other stuff to detect leaks. i myself use a stethescope(sp). works great.

 

I thought it might be a vacuum leak but i coulcnt think why it would only be when the car hasent been running for a while. How do they use carb cleaner to look for leaks?
-Mark

 

spray it around areas where a gasket is or might develop a leak.
spraying the cleaner around the area while the engine is running would make a difference in the idle if a vacuum leak was present. i.e. idle would go up temporarily. (until you stopped spraying)

 

I have a similar problem on my bird, if I let it sit over night the only thing that will get it started is starting fluid into the throttle body, but after its started i have to keep it up around 1,500Rpm for a few secs otherwise it dies, im wondering if its the cold start valve.

 

My 86 was doing the same thing. I tried to replace the cold start valve, didn't fix it. I ended up taking the IAC valve out, cleaning the top of the valve, and the cavity it fits in, and re-setting the minimum air rate, and reset the TPS. It hasn't done it since.
Hope it helps

 

Thanks for the help, I would try that but I honestly dont know where the IAC valve is
-Mark