Ford Repair: 2000 ford crown victoria, ford crown victoria, air control valve

Question
I have a 2000 ford crown victoria it idles high in drive and drop back to normal idle its fine in park and when I am driving picking up speed fast when I get off gas the engine is still reverd high and then it will reverd back down can u help me

Answer
Well you can start by cleaning the idle air control valve and throttle body with spray and a cotton cloth.
Follow proper procedures and techniques.If the check engine light is not on and suspect a faulty throttle position failure.You can test  the ohms to the connecting wires of the TPS and compare that to normal parameters.Usually found with proper instructions in a service/repair manual.Have the engine codes read if check engine light is on.