Hi bought a 1989 iroc z camaro back in dec. just kept starting it over winter to make sure it drove got it inspected last month (it had been sitting for 2 years) drove it for about 3 weeks and now it wont idle correctly.

the engine is a 5.7l v8 tpi with about 90k miles

so when i start the car the engine turns over and sounds just like its about to start but then goes down to where it idles from 1k rpms to about 500 when it drops to 500 it doesnt stop and turns off. if i keep my foot on the gas it runs fine and everything (the last week ive been basically doing this to get to/from work)

i checked for vacuum leaks and didnt find any, i also changed the fuel filter to see if that would effect it.

any ideas what to check or do? please be detailed im just learning as i go with cars in general as my dad wasnt a car guy and im only 19=p

i was looking in the haynes manual and iwas thinking maybe something with the iac or distributer cap??

thanks for any replies or suggestions

oh almost forgot it is an intermittant problem does not happen every time i start some days it does some days it doesnt

 

A good start may be to clean the throttle body and IAC.

 

also check your tps and maf sensor. unplug one at a time and start the motor. if it runs better with one of them unplugged then thats probably the cause. also take a look at the idle air control valve.

 

After I put in a different engine I had this same problem with a 99 Grand Am. It could be many differenent sensors. Luckily I had all of the sensors from the old engine so I just kept swapping them until I found the problem. Mine ended up being the O2 sensor so you might give that a try.

I would start by cleaning or replacing the MAF and the IAC and see if that helps. I would do the O2 sensor after that. I was even told that it could be the EGR valve or MAP sensor as the cause.