Engine/Transmission (1998.5 - 2002) Major Stumble

[Bloomy]

Friend of mine picked up a 99 QC auto a few months ago. After taking care of starter contacts and a few other little things it now has a major stumble and stutter at or around full throttle. If you drive "normally" it is ok. But, when you go to punch it, it stumbles and sputters. Any thoughts?



Thomas

 

[Turbo Tim 1]

Need more info, Does he have an Edge Comp or other performance box? If he does then he needs to redo the ground connection.

 

[sfritts]

I Would check the fuel filter, and lift pump pressure at full throttle. One batch of dirty fuel will slow down the fuel filtering, and a weak lift pump acts as you have stated.

 

[Bloomy]

The truck is completely stock. I was leaning towards the lift pump as well. I think we are going to replace it regardless and install a fuel pressure gauge. This is his first Cummins and he is getting impatient with the problems. (hunting transmission, starter contacts, lift pump) Thank god for this site so I can stay on top of what is going on and get less expensive better repairs for some of the problems. Thanks for the suggestions. I will let you know.



thomas

 

[Mundgyver]

Replace the lift pump with a FASS or a Preperator and open up the fuel line to 3/8 ID including the input to the VP. Volumn of fuel is a wonderfull thing for a VP, especially with 17 psi constant.

 

[Bloomy]

It ended up being a really nasty fuel filter. I think that I can talk him into the Fass, but it will be a little while. Thanks for the help.



Thomas