Fuel problems?

[turbo3500]

I am currently driving across canada and I seem to be having problems. When my 2007, 5.9l cummins turbo kicks into overdrive it seems to run fine. When it lowers its gears it sputters? Theres no smoke coming out of the exhaust so, maybe the injectors are being flooded or starved? Ive replaced the fuel filter, so far ive driven 4000km but this isnt near the first time this truck has driven like this. Any suggestions as to what it could be? I also want to know if its still safe to drive

 

[turbo3500]

Also forgot to add it vibrates while in lower gears. Its not U-joints or anythings thats all new before I leave on these trips.

 

[Redtruck-VA]

Don't know diesels but it also sounds to me that you have a fuel problem. The vibration lets hope is the engine stumbling under load. Are you getting any codes? Sounds like you need a dealer to check it out.

 

[turbo3500]

Im thinking fuel problems and the torque converter. My buddy has a computer so if I make it home ill hook up to it and see whats happening. There isnt a heavy load on this at all. Ive hauled 17,000lbs for 5000km(2 years ago) with no problems. I only have a small speedboat on this trip.