My 2001 cummins pulses mainly uphill. I step on the throttle and it stops. But regular driving on flat highway or uphill it pulses. I have heard that this means the turbo is going bad. Is this true?
Everything is stock. The VP44 is after market and so is the lift pump. But that is the only thing that has needed changed. I would appreciate some input from someone.

 

How many miles on this truck?
Automatic or manual?
Do you have gauges and do you see any anomalies like turbo boost surging, FP fluctuating?
It is probably the APPS (accelerator pedal position sensor). Trucks that run the highway a lot at one speed typically wear a spot out on the reostat in the APPS.

 

It's an automatic and has only 138,000 miles on it. I don't have any gauges to show with the Boost is on the turbo just the stock gauges that came with it.

 

It's an automatic and has only 138,000 miles on it. I don't have any gauges to show with the Boost is on the turbo just the stock gauges that came with it.

 

Its very hard to tell whats going on without gauges, but you could try a re calibration of the APPS.
https://www.dieselbombers.com/98-5-0...ting-apps.html
If it is happening while going down the road with the pedal at a certain spot like I said it may be a bad spot in the pedal assembly reostat.
Also lift pump fuel pressure is critical in this year of truck we need to make sure the VP44 Injection pump is getting at least 10 psi @ cruise throttle.