Help me help a friend please!
 

Ok guys my buddy from since I was a kid and a good fishing buddy at that currently has a sick cummins. It's an 07 5.9 ram 2500 ext cab.

What we both thought was a bad fuel filter after replacement has not fixed the problem at all.

When the truck gets warmed up 5-10 miles down the road it will shut off. After hooking up the scanner it is saying it is starving for fuel.

Could it be the gas vent being clogged? It has a lot of built up pressure when you open the cap. He is gonna give it a run tomorrow to see if venting the cap helps but I'm trying to find out any other reasons why it would be running like crap when warm.

We know it's fuel related, maybe the pickup is clogged? Or a bad lifter pump which would cause the injector pump to work twice as hard?

Help me guys i own a 1st gen 12 valve and I have only worked on all mechanical cummins without computers so I'm as stumped as he is.

Thanks guys!

You really need to hook up a gauge on the supply side to the CP3! But even if the lift pump is bad the CP3 will still pull fuel! I think you have a Cp3 issue try to unplug it and see how it sounds it should sound like it's going to self destruct then plug it back in if it keeps running! If it dies there it is!

If it was the cp3 then the lift pump wouldn't make enough pressure to keep it running

If it was the lift pump then the cp3 would keep it running long enough until the ECM shuts it off because it's being robbed of fuel?