Ive got an 04 cummins and it starts and runs fine. Wide open in neutral runs good. Anything over 16-1800 rpms it runs horrible. Missing and no power. I changed the filter again and power service still runs like junk. Any ideas?? lift pump?

 

Do you have a rail pressure gauge?

 

Or even a low-side pressure gauge? How about codes set? CEL on?

Gonna need more info...

 

no guage. the trucks in the shop. They had called me last night saying they thought it was jelled. He said fp looked very good. However 16-1800 rpm it misses like its running out of fuel. Took the truck back to the shop last night. I was just wondering what could be wrong with it??

 

Fuel pressure gauge(s) just might be the most important instruments you can run on these trucks.

 

I havent installed guages yet. There ordered but not here. The shop said theres very good pressure though. So what else could it be?

 

If it was gelled like they said, then all is well now.