I just got this vehicle from a friend of mine who suggested I ask the DTR community about this issue.

When I get to about 2K rpm I start to lose power and blow whit smoke. This happens at all gears and is so bad sometimes a cannot go faster than 55 mph! But then sometimes it works for a few miles and then back to the power loss. I tried seafoam but not much improvement. Any help would be greatly appreciated! From reading the posts here, it looks like I am in the right place.

Thanks!

 

Check that the fuel return "overflow" valve is good, by pinching the rubber return line.
If the motor revs well when the return line is clamped, then returns to sputtering when removed, replace that valve.
DO NOT run the truck with the return line clamped off for longer than needed to diagnose.
I use a small vice grip.

 

This can also be a symptom of injection timing that is very late. By your description though, it sounds intermittent, and a timing problem should be fairly constant.

Another couple of things to look at are, a binding fuel shutoff solenoid that doesn't pull up fully when the engine is started, and air getting into your fuel supply system.

 

Fuel filter is a good place to start with a new truck. I would save the guessing and install a fuel pressure gauge at the same time, great to have for troubleshooting. Great write up on fuel pressure. How does it run at first start of the day?

 

Thanks! These all sound like great ideas. Do you think it could be the lift pump also?

 

Sure could be, if with a fresh filter you pinch off the return fuel line at idle and don't see a dramatic increase in pressure (up to ~60 psi) the lift pump is most likely the culprit.