in my truck the engine seems to have a miss,its a cummins 460 N14 electronic,when i'm shifting a grab a gear and step on it,the engine kinda flutters then starts to take off,when i'm working the motor it kind sounds like its missing (slightly)this is a new problem.Also this is an old problem,when it is sitting,idleing,it slowly starts to rev up on its own it will rev up as high as 1500rpm and will fluctuate up and down from there,been in to countless shops and dealers with no success.when they put it on the scope it does'nt show fault codes therefore they say there is no problem.ever heard of this?been doing this for 6 or7 years semms to be getting worse though.