Idle Problems-Different

[meshoman]

I know everyone has read about a thousand idle problems, but... My car will not idle cold. It will start, run for a few seconds and stall. I can restart it and feather the gas to keep it running. It will then surge from about 500-1500 RPM, then after about 3 minutes, will idle rock solid. When first started it will also stumble like it's missing when you hit the gas. This also goes away after about 3 minutes. I have no codes, the ECT and ACT sensors read out fine when warm, I have checked for vacuum leaks everywhere and I've gone through the Probst, Ford Fuel Injection book trying to troubleshoot. O2 sensors are fairly old, but supposedly the computer doesn't look at those until they heat up. Plugs are new, ignition is new, plug wires are new and timing is set @ 14 deg. I got nothing. Any ideas? Thanks!

 

[jrichker]

See the sticky "Help me create the Surging Idle Checklist" at the top of the forum for help with your idle problems. The first post has all the updated answers.

 

[pistonhead351]

my best guess would be IAC. not letting enough air in.

 

[meshoman]

Wouldn't a bad/defective IAC cause idle problems all the time? My engine idles fine after a few minutes...

 

[pistonhead351]

im pretty sure that the IAC lets more air in the motor on startup for the first couple minutes then after that it does nothing.

 

[HISSIN50]

As said, the IAC is most critical at start up. The info in Jrichker's thread will provide answers and procedures.

Good luck.

 

[meshoman]

OK. I'll try going through jrichker's thread again. Thanks, guys...

 

[meshoman]

OK, I just replaced the IAC. No difference. I pulled the EGR valve and cleaned it. It seems the pintle may have a very slight leak when closed. Could this cause it to not idle, then idle perfect after a few minutes? Again, no codes, no vacuum leaks, everything else except O2's are new...