My car has been running exceptional until last Friday.
Here's what happened:

Went on a trip from Pennslyvania to Virginia. Car ran great on the interstate just like it did where I drove it locally. After two hours of steady driving between 55- 70 mph. I pulled off the interstate to get gas and my idle wouldn't drop below 1500 rpm while stopped or in park. I thought that the gas pedal linkage was sticking , but it wasn't. I shut the car off to get gas and when I restarted it, it idled normally. Same thing happened when I arrived at my destination. High idle at the first light it stopped at and it didn't drop until I shut the motor off and restarted it.

No trouble codes at all. I had a code 44 a few days before I set out on the trip , but it wasn't idling high when the SES came on.

Same symptoms on the return trip home.

Everything [And I mean EVERYTHING!] has been changed sensor-wise on this car including the EGR valve the FPR, ultrasonically cleaned injectors, rebuilt dist. new plugs and wires. ect........

I even reset the minimal air flow on the throttle plates and reset the TPS voltage according to the info provided on this board.
Can't figure out why the idle won't come down after a trip averaging 65mph. It doesn't do this during normal around the town driving.

Any suggestions?

BTW-----The IAC and the TPS are both new. Maybe I got a bad one perhaps. Has anyone out there ever has this same occurance?

 

My buddy had an old truck with this problem....but we never solved it! Have you checked all of your vacuum lines? Code 44...is that an O2 sensor code? If so, has the sensor been changed recently?

Also, have you tried resetting your ECM and seeing if the problem goes away?

 

Did you clean your IAC passages?

 

IAC passages are spotless. EGR valve has been blocked off at the plenum so there's no chance of the passages getting "coked up".

All sensors have been replaced within a two week period after I purchased the car. FPR has been replaced. New EGR although it's blocked off. Injectors ultrasonicallyed cleaned. New intake gaskets, distributor rebuilt, new plugs, cap and wires, new PCV valve.

Car runs fine except when I'm exiting off the interstate. It seems that during an extended run of 65-70 mph the idle won't kick down to it's normal setting. It rev's 5-700 rpm's higher in drive. I'm thinking that the new IAC is defective somehow. It won't reset itself after coming down from that aforementioned speed.
Driving around town and even at the 55 mph range is not a problem. The idle always comes down to normal after driving in that scenerio.

For what it's worth, and I doubt that it's relavant. That "code 44" started after I replaced my water pump a few days before the code set and before I went on that trip. I know that no wires were disconnected or loosened with the exception of my MAF sensor which I removed to get better access to the water pump.