2005 duramax 6.6 LLY w/ 109000 miles, engines never been worked on except oil and fuel filter changes. I have run an hyper tech programmer for several years. Its driven on weekends mostly and vacations. 10 miles after last fill up my truck start bogging down when fuel peddle is pushed past half throttle. Runs fine at idle and cruising speeds, but if you need passing gear and it bogs down and would probably quit if you held it there. Hold it about half and it will only run about 65 mph . Changed fuel filter (ac delco ) still same problem. Took programmer off still same problem. the programmer said it had these codes p0401, p0404 and U1093. Ive worked on trucks before but never diesel engines. Just wondering where to get started. Bought a Haynes Service Manual today.

Thanks
PS Just found this site today, Im very hopefull

 

Looks like a couple EGR codes not sure about the U1093 though.

I am not good with Chevrolet diesels either. But here's what the tech manuals are saying about the codes.

dtc-code-p0401 2005 Chevy.pdf

dtc-code-p0404 2005 chevy.pdf

 

thanks, im gong to try and clean EGR valve

 

Well hooked it up to a better DTC reader and it said that the P1093 code: is loosing fuel rail pressure during power enrichment. Hmmmmm !!!

 

For anybody that's listening or reading the problem i was having was caused from the Fuel pressure relief valve by-passing under heavy load.

Thanks