2002 Duramax Loss Of Power

[xtrmss]

My father has a 2002 3500 crew cab with the LB7 Duramax in it, and has had the injector TSB replace all injectors done about 20k miles ago. It seems to have a loss of power while pullling a heavy load. Have changed fuel filter and nothing changes. Watching the Desired/Actual fuel rail pressure while pulling, it will ask for 19k-20k and only get 13k-15k. Once you level out or get on a downhill run the actual will slowly creep up to desired. Unloaded but standing on the throttle the actual still is off from desired by 4k-5k. It seems to not be able to keep up while under a load or heavy acceleration. I have a 2004 LLY and my actual/desired doesn't fluctuate much under any load. Is this just a typical of the LB7 or is there something wrong. He took the truck by dealership, they said injector balance was fine, it only had 2.5 inches of vaccum at the test port, and everything tests within specs.

[wawa]

check for fuel leak on high pressure side of fuel system is he getting fuel in the engine oil the fuel pressure drop is probably due to a failed seal or a bolt that has worked loose.

 

hope this helps

[KENNHON]

check for fuel leak on high pressure side of fuel system is he getting fuel in the engine oil the fuel pressure drop is probably due to a failed seal or a bolt that has worked loose.

 

hope this helps

 

What about the lift pump?