i have a 2003 dodge 4 wheel drive , automatic, cummins, at 2100 rpm that is all the faster it will rev going down the road, free rev it goes right up , real slow on take off , up winds up there, no real mods , new injectors, kn filter, it just has no guts going down the road enpty , help thanks , does throw a 336 code , but maybe once a week , changed the crank sensor , no change, thanks

 

You must have bought my old truck. I had a 2003 Cummins that had NO power. It struggled to tow anything, and got 6 mpg while towing. Took it to the dealer three times in a year with complaints of "no power". The dealer never could find out what was wrong with it, so I traded it in on a Duramax after a year. Good luck with your truck.

 

Wiring did you check the wiring for the crank POS that wiring harness gets screwed up sometimes... that is my

 

2003 cummins , will a shorted or bad injector throw a 336 code, it misses when it throws this code, thanks

 

I had similiar issues with my 03 HO. I had it to the dealer and they couldn't fix it( injectors,lift pump,ecm,fca were replaced). I talked with a Cat diesel engineer who told me to remove and clean all my ground connections. Not just the battery grounds, all the grounds. I sanded or wire brushed them. I found a braided ground attached to the back of the head it was nasty. After the cleaning my truck ran great. Try it and hopefully it'll work for you too.