Scotty, just bought a 2002 Lincoln Continental with 161,000 miles for $2,900.  4.6L DOHC V8, 4 speed automatic. Noticed today that the throttle seems to stick intermittently while the car is being driven.  The RPM will either not return to idle while the car is coasting or stay in the 2,000-3,500 range even with my foot off of the gas pedal and at a complete stop.  I have to pull over, put the car in park, and rev the engine really high temporarily then let off the gas to get it to return to proper idle RPM (Below 1,000).  Even turning the car off does not solve the problem, it still jumps up to around 3,000 RPM when I turn it back on and I have to rev it a few times to get it back to idle.

I have cleaned the throttle body plates and idle air control valve. I've also ensured that the throttle cable or any attached hardware is not physically getting stuck in any way. The gas pedal is not physically getting stuck either. Still having the issue if I give it too much gas. No check engine light or codes.  All fluids are clean and at proper level (aside from the power steering). Don't know if this can related, but I do have a power steering leak that needs to be fixed, lots of fluid causes smoke to come from the hot engine bay.

Thanks for any input!