2001 5.9 Cummins Rough running
 

I have been trying to sell my cummins due to having a baby and starting a Paramedic class.. I have had a few people come and look at it and they all say that when u go down the road at high speeds it feels like it is "missing" its starts fine and idles fine and runs fine until those speeds and no dead pedal
it does sound like the inline fuel pump (which is just an aftermarket pump on the frame) has a loud buzzing noise so idk if the fuel pump is gone bad and idk if it can cause these symptoms
I have no codes present and i haven't checked anything yet just trying to get an idea of where to start... I need to get this fixed in order to get it sold and I'm really hoping it is not the vp44

Any help is appreciated!

first off congrats on the new baby.:tu:
second, thank you for your service to your community:tu:
it is possible that the aftermaket fuel pump is going out. You can crack the fuel lines off of the vp 44 and see if your getting fuel out of the lines.
Or you can remove the lines off of the aftermarket fuel pump,and connect them back together in stock form and retest drive the truck to see if it has the has miss at the same speeds.If it doesn't than it sounds like that is the issue.

Thank you very much... and thank u for the information I'm gonna work on it in a day or 2.. I'm thinking it is either that or the fuel is gelled really bad in it due to the severe cold we r having so I'm gonna warm it up in the barn and do as u instructed to see if I need to replace the fuel pump... thank u again

check your air filter. any heavy blue or black smoke when it misses?

Have you changed your fuel filter recently?

I just replaced the fuel filter and checked the fuel pump and that is pushing fuel, I don't believe there is any smoke when it does this... but i did get some codes off the truck now.. p0500 p1765 p0622.. hope this helps guy I really need to figure this out because there r quite a few people interested in it and I don't really want to pay to have a mechanic look at it unless absolutely necessary