93 mercury sable (wagon)

have a problem with idle speed.

Occasionaly the idle speed will run high (about 1250) and will not come down
(typically about 750), it has also gone up to 3000 on rare occasions. Have
not been able to figure out a pattern but turning the car off and restarting
seems to at least get it to normal for a moment.

This is the 3.8l multi-port injected engine, how is the idel spped contolled
on these engines and anyone have any suggestions on what to start replacing
TPS maybe?


Thanks for any help.

Steve R