Any ideas will help here.

My wife's '01 T&C idles high. She said it was idling at 2k and remains there until she puts it in gear then it drops to 1.5k. Also, when driving at moderate speeds when she takes her foot off the accelerator the van maintanes its speed. Would this be caused by the throttle position sensor?

 

Try cleaning the throttle body and butterfly. Use ONLY an intake cleaner that is safe on plastics.

In fact, don't spray the cleaner directly in, just soak a lint-free rag and wipe the outer and inner edges of the butterfly and the mating surfaces.

Edit: You may want to look for an air leak as well...a cracked inlet hose from the air cleaner for example.

 

I will check those things today. Autozone checked the codes for my wife and it came up with "idle speed not achieved."

 

Remove the throttle body and clean, also remove the ais motor and clean as well. If that don't help maybe you have a vacuum leak.