Hi,

I drive a  Ford Focus 2002 1.8 Zetec estate and I have been having some trouble with it since I bought it last August.

The car now accelerates on its own and can pick up speed very quickly without my foot near the pedal. When the clutch is pressed to change gear, the revs climb to 4000rpm but they drop back down when the clutch is disengaged. I have done work on the car to diagnose/treat the underlying issue myself, but I’ve had no luck.

Any help would be much appreciate 

 

Sound like a faulty throttle position sensor or a gummed up throttle body. I would first try cleaning the TB then concentrate on the TPS. 

Yer ive cleaned throttle body, should i be able to see light coming through it? and replaced the throttle body sensor but still the problem is still there 

When changing anything like that the ecu has already learned the previous values. Disconnect the negative battery terminal for about ten minutes but make sure you have your radio code. Then it should go into relearn mode. Also check for any split hoses as that can increase rpm to compensate. I would first check out the pcv hose and valve if after the relearn it's still the same. You will need to drive around for a bit during the relearn process but if the rpm problem still exists then you will know.