Sounds like it needs a new IAC (Idle air controller). PCM sounds fine if that is the only issue. It's normal for idle to increase with A/C cycling, but not 2000 RPM. The IAC is tucked down in on the left side of the intake manifold.

Also, clean the throttle body by hand with cleaner and a rag. Th rag should turn black. Buildup around the throttle blade will reduce the idle speed slightly. Cleaning it will restore idle speed maybe 50-100 RPM.

Al

 

Hi, I've replaced the IAC twice (last fall n this winter) used Motorcraft IACs. Also have replaced the MAF and TPS modules.Sprayed the throttle body with throttle body cleaner. Did a continuty check from IAC connecter to pin 83 on ECM connecter - tones out good. I have been using an ODBLinkMX+ for ODBII scanning and Forscan scanner software. The scanning reports no errors. I have dumped memory in the ECM by disconnecting the battery. Have driven car for ECM to relearn its operating settings.

I think I have tried most everything possible, the only thing I haven't changed is the ECM.

Thanks
VWW

 

A used PCM should not be too expensive to try, but a little hard to find. You'll need the catch code - typically located under the hood in the right rear corner.

Here is a good website for used parts. You can call the junkyards and have them ship the part. Or if you have one close enough, you can drive. Car-Part.com--Used Auto Parts Market

Al

 

Thank You for the link. My ECM is a F4WF-12A650-BD / D4L3, ML1-101, 03/14/94-3, EEC-V. I will check with parks link.

 

No problem. There should be a sticker under the hood for the catch code. For example, a 96-97 code is "FTE-1". There probably is not much difference, but good to match it if you can.

Al

 

Thank You T6Rocket for providing the parts lead ( Car-Part.com--Used Auto Parts Market ), they had an ECM (EEC-V) exactly matching mine F4WF-12A650-BD / D4L3 and the car is working perfect.
So... 9 months of trouble shooting and learning digital car technology, 2 repair shops ( 1 supposably a tuner shop), approx 3000+ dollars the car is running great.
Now I am looking for a repair service that does ECM board repair on my original ECM that has the idle air control driver (transister blown) circuit damaged.
The problems I had was, cold engine when starting would not hold (desired cold idle from ECM) and random RPM revving after warmed up. Not a common ECM problem.
Again, Thanks for the help.
VWW