Hi all. The revs on the 1.8 si zetec in my 100e take ages to come back to tickover after revving. Any ideas why this would happen?

 

TPS or TB ? really depends on what running gear your using

 

Ok. Could it be the TPS out of adjustment? The actual plenum chamber has been modified to fit in the confines of the engine bay. The runners are now angled at 45deg pointing forward and about 2 inches longer than originally. The engine sits right back in the engine bay with about 8 inches in the car. There wasn't enough room where the pedal box was to fit the plenum chamber so it was bought forward to make it fit.
What could be the issue with the throttle body?

 

Try removing the throttle cable and see if it still occurs.
Check the spring return action of the throttle body is free to close under its own effort.
Had this on my BMW and it was simply I'd routed the cable wrongly round the engine after a bit of work.
Used to fix quite a few vw transporters with a sticky throttle cable simply cos it had come off a few clips round the bay etc.
Caused all sorts of issues!!!