I have an 02 reg cab 5.4, and when im parked and pump the throttle, the revs jump up respectively quick but return to idle very slowly. It takes around 2-3 seconds whereas my dad's 99 supercab 5.4 returns almost instantaneously.Whats up?

 

check your TPS, this could very well be the problem and also check to make sure that the throttle body doesn't need to be cleaned.

 

Thanks , you just helped me figure out why mine has been doing that . I have 3 or 4 different TPS's and I think I slipped a different one on it when I had it apart the last ..

I didn't think about that untill I read this..

 

Im new to f150's as i just got this one, i had a 5.8 bronco before. can you elaborate?

 

Cleaning your TB and IAC - Click on the link -

http://www.fordf150.net/howto/throttlebodyclean.php

 

TPS = throttle position sensor
THIS IS NOT EXACT but this is what one looks like:


As jbrew said, clean throttle body, IAC valve and don't forget the EGR ports too.

 

Chances are it is normal. Ford uses the slow return to idle for emision reasons. If the throttle plate slams shut quickly, one aspect of the emisions is high.. I think hydrocarbons or NOX. Ford has been doing this since about 1981 on most of there vehicles.