I have a 2002 dodge ram 2500 4wd with the v10 and 98,000miles. whenb i start it in the morning it will idle at about 1500-1700rpm then jump back and forth till it settles at about 600rpm after about three minutes. then while driving down the road it the rpm will lunge and it feels like the truck is bucking somwhat. it does this considerable worse if you use the cruze controll. any thoughts?

 

Possibly TPS. (throttle position sensor.) You can test it with a volt meter.....