Hey, I am posting this for my father. He has a 96 ram that surges about 2-400 rpm at highway speeds. He replaced the coil to an Accell and it got a crack in it somehow and when he replaced it with a stock coil the surging appeared... is it the coil, or what? Thanks and happy holidays!!

 

Check the Throttle position sensor

 

Common of the throttle position sensor, I have heard of many dodge trucks doing this. Definately change it before driving much more as many of them can get worse and feed the engine full throttle while not even touching the gas peddle. These going bad have caused many accidents since people panic and don't think to simply turn the key off.

 

TPS is the first thing I'd check. You can get one for 30-40 dollars at auto parts stores. Takes 5 minutes to change it.