I recently purchased a 2001 Chevy 3500 HD with a 6.5 Turbo Diesel. I drove it 300 miles to my other place in Northern Michigan. About 200 miles of this trip was in heavy rain. The truck seemed to run good until I came to some hills on the interstate. The truck lost speed on the hills from around 70 mph down to about 55. I could not make it go any faster as long as I was going up hill. Once over the hill it would return to 70 mph again. This seemed like an excessive power loss since the truck was unloaded and not pulling a trailer. I suspect maybe a partially clogged fuel filter. I'll admit that I know only a little about diesel engines but this did not seem normal to me. The truck has 120,000 miles on it. I would aprreciate any thoughts that anyone would have on this. I am now in southern Michigan for the winter so I don't have access to the truck. I'm looking for opinions and possibly suggestions for the spring. Thank You.

 

sounds like the turbo isnt working if it is try filter n some diesel treatmnt use a stanadyne additive.

 

i would do OPS and LP test and check all ground and clean but it also could be PMD going south

 

ip

 

LP lift pump

 

Bad fuel change filter.