i noticed today my truck ( 91 f350 with 5.8) started trying to jump forward when at a traffic lite, when parked and idling it idles fine for about 3-4 sec then it jumps up a few hundred rpms for like 2 sec then back to normal, just keeps repeating. does this sound like a 02 issue?? i just had a new exhaust put on yesterday with new cats installed if that helps with any thoughts.

 

Check for a vacuum leak around the engine. You could also see if you have any error codes stored. Go to fordfuelinjection.com for instructions on how to and while there read up on how to clean the Idle Air Control valve as this may also be the problem. But check for vacuum leaks first.