Hey guys!

I'm helping out a friend that has a 1989 302 V8 with the EFI. It's run perfectly for years, and has now suddenly stopped idling properly. Up until yesterday, I could start the engine cold and it would start right up on fast idle, then slow down after a few seconds. Nothing has been replaced, or changed.

It's got new plugs, wires, distributor cap and rotor. All I know about the EFI is to check for vacuum leaks, which I've found none. A few months ago, we replaced the throttle position sensor.

Got any ideas? We've run a bottle of GumOut into it. There's no water in the gas. I took it out and blew out the engine on the interstate. Runs great at highway speeds, but no idle.

Thank you in advance!

Bruce

 

Wow seems like today is the Day for IAC's eh?
Anyway if it's an idle issue check that out and clean it up with some carb cleaner.

 

Had an issue with wifes 2 prevoous cars. Both turned out to be throttle body was gumed up with exhaust residue, the throttle plate was not closing or possibly opening, remove the throttle body for better access to clean proper this also allows for use of a good cleaner not affecting air flow sensors etc. Could also be under the intake exhsust/fuel ports possible air flow restricted.

 

Use a scanner and check the fuel trims, if you think it may be the injectors connect a gauge and run an injector leak down/balance test