motor runs great but at times the idle increases from normal 700 to 800 rpm at idle to 1100 to 1200. If I come up to 10 stop lights I would say I see the high idle 3 out of 10 stops, any one know if this normal or how to fix this possible problem?

 

Welcome to the site. I will move this post to the Dodge Cummings Diesel section,
FF

 

Just to help us out a little bit what trans do you have in your truck auto or manual?
Since the throttle is controlled by the computer.
It may be the pedal is sending the wrong signal to the computer
but it should send a code and kick the check engine light on. Just for kicks check the floor mat and see if its pushing the pedal
hope that helps