Ford Repair: idle surge, air control valve, air jackets

Question
Ihave a 94 taurus. While in park motor revs up & DOWN.PUT IT IN gear and runs fine. No engine check light is on.

Answer
This sounds like a dirty Idle Air Control Valve. Remove the duct work from the air filter to the throttle body. Using a cotton towel, spray air intake and throttle body cleaner wiping the dirt out. Opening the throttle wide pen will let you clean the throttle body even better. What has happened, is the air jackets that let air pass through at an idle are clogged. So you just simply need to clean them out.