Ford Repair: Ford Escape 04 auto, cotton towel, throttle body

Question
when started and still in park my car is idleing below one but sounds like a dog panting repetativley like a heartbeat its like it keeps reving out then going down but after i put in drive and start going its unnoticeable i am not sure why this is happening got a recent inspection last month and everything was fine only one owner but 80k please help.

Answer
Clean the throttle body, it's about time. This isn't done with additives. You manually clean it out at the point of this idle control. http://i289.photobucket.com/albums/ll223/james_corn/Idlecontolunit.jpg
This control unit mounts on top of the throttle body. Due to engine bypass air after the air filter, you're throttle body gets "gunked" over time. Have it cleaned, inside, with a cotton towel, idle air and throttle body cleaner, and a strong finger.