Idle stumbles in park

[MrTeeThyme]

My 2003 stumbles really bad when I put it in park. It usually recovers ok but sometimes it stalls. I've cleaned the IAC and replaced the EGR valve. The PCV valve elbow is ok.

Any ideas what to check next? I'm not getting any codes or CELL.

 

[ncranchero]

Still sounds like IAC. Cleaning won't help if electrically defective.

If you have a VOM multimeter you can check it.

KE3 CHECK IAC VALVE RESISTANCE
IAC valve disconnected.
Measure IAC valve resistance.
Is resistance between 6.0 and 13.0 ohms?
Yes GO to KE4 . No REPLACE IAC valve.

KE4 CHECK IAC VALVE FOR AN INTERNAL SHORT TO IAC CASE
Measure the resistance from either IAC valve pin to IAC valve case.
Is resistance greater than 10,000 ohms?
Yes GO to KE5 . No REPLACE IAC valve.

KE5 CHECK AIR INLET FOR PLUGGING OR STUCK IAC PINTLE
Inspect the entire intake air system for debris, blockage and other damage.
Remove and inspect IAC valve, check pintle movement. Check air tubes (if equipped) for blockage and other damage.
Remove and inspect the air cleaner element for excessive dirt.
Is the IAC valve and intake air system OK?
Yes RESTORE inlet air system. No REPLACE IAC valve or repair air inlet as necessary.

 

[MrTeeThyme]

Thanks. I'll run those checks and let you know how it turns out.

 

[MrTeeThyme]

These tests all turned out good. !0.9 ohms pin to pin, no short to the case. I hate to spend $80 on the chance it still won't resolve the problem. But hey, at least I'm not paying labor.

What does it mean that I have greasy residue around the pcv valve? Could a bad pcv valve contribute to this type of behavior?

 

[ncranchero]

If it's stuck open it is basically a vacuum leak, introducing too much air, just like a stuck open IAC.

Yes.