Cadillac Repair: excessively high idle speed, throttle position sensor, vacuum leaks

Question
Problem:  1994 Cadillac Concours DeVille, one owner, that idle speed runs very high when engine starts and continues to run at an excessive speed during driving. Problem has become constant and you have to keep foot on brakes to keep the speed down.  This problem happens if going forward or backward.  Any information you can help me with would be gratefully appreciated.

Kip Clark, North Carolina

Answer
Hi Kip, Sometimes when this happens it is due to the battery being changed or engine computor lost power and it didn't get the idle relearned. If that isn't the case then vacuum leaks/big vacuum hose left off, throttle position sensor sticking at a higher voltage or the gears in the idle speed control motor bind and the idle can't come down. If nothing is obvious then getting it to a shop for diagnosis will be needed so you don't have an accedent. Happy New Year. Bill