high idle after driving

morning all wondered if anyone could shed some light on this problem. p38 4.0 thor engine. Start the car and its fine rev it and it ticks over at normal tickover speed drive it and it then ticks over between 1500 and 2000 rpm. Turn it off and start it again and tick over is back to normal. Ive checked the throttle cable and its not sticking any thoughts on potential problem. Cheers Jason

Sounds like something to do with the throttle position sensor. You need diagnostics to look at it's output though.

You can also try cleaning the IAC (idle air control) valve.

Whats the best thing to clean it with carb cleaner? just been out in it again and throttle doesn't feel smooth at all. ive got a spare throttle body in the garage think ill rob the throttle position sensor out of it and try it in