Racing engine after start

You could check the TPS voltage (should be .98-1.01, they say) TPS = Throttle Position Sensor Part # DY967 (from motorcraft)

Or, you could try the "teach the throttle some manners" routine:

Engine off Turn ignition to ON (do Not start) Wait ten or a couple more seconds Press the pedal all the way, HOLD ten or a couple more seconds Release the throttle s-l-o-w-l-y Turn ignition OFF Wait ten or a couple more seconds before starting the engine.

This procedure is reputed to remove some lag from throttle response, as well. Couldn't hurt, and it's free!

PS: Here's another version that's been going around: Recalibration Procedure for Throttle: Turn Key ON. Wait for dash lights to go out. Press throttle fully to floor quickly and release quickly. Turn key OFF.

Let us know if it works.

I never start the stang with the AC on, it tends to mess up the "learning" for a while.

Wild ass guesses; Perhaps the air bypass is dirty ? Or Throttle cable is sticky ?? Could have a bad spot in the TPS ???

With this throttle by wire system, the place to start is going to be scanning for codes and perhaps running the KOER On Demand test... Much can happen in the two months since codes were checked in the car and this is going to have to be one of the early steps to try and eliminate any guesswork.... There are many concerns that will not turn on either the wrench light or the MIL....

Without knowing where you live or the prevailing weather conditions, there is even the chance that ice may be forming around the throttle plate. The actuator should be strong enough to break any ice but....... If icing is the cause, you *might* expect a P2072 or a P2111.

FWIW, I have an '06 V6 Mustang that's had this problem since it was new, yet the dealership keeps telling me they can't reproduce the failure. Mine only races up to about 2500 or so, but exactly like yours, will drop down to 7-800RPMs or so when I reach a stop (I don't have to wait a minute for this though - only about 2 or 3 seconds). I've since learned to work around the problem by re-starting the engine after five minutes of running. Kinda sucks having to do this, though... Initially, I was hoping a custom tune from Bamachips would fix the problem, but it didn't seem to make any difference.

Hi folks, First, thanks to all who responded I was able to get an appointment at the local Ford, Merc. Dealership this afternoon. I have the utmost faith in their shop, the tech's that I have met all seem very professional and knowledgable. The Service Writer told me all the codes check fine. His suggestion was to keep using the vehicle until it gets much worse, and to leave the airconditioning switch in the off position until the car is started. I really symphonize with the tech's when they must waste their time with a intermittent problem. For Jim: I live in Rogers, AR. hot and humid in the summer, other times of the year we still have the humidity, but the temps are tolerable. Having worked in General Aviation all my life, I appreciate your concern about "Carb Ice" Once again, thanks to all. Steve