6.5l stalling

[BB123]

Hey,
I'm new to the forum but not to the problems with the 6.5l. It has a new injector pump, pmd, Fuel/water seperator filter also i've cleaned the fuel tank just in case. But the truck will run fine sometimes then other times cuts out alot and at idle will sometimes go dead. It seems ok usually the first 15 mins of running. I don't know it just runs like it wants to. Thanks for any help

[65TD]

You test lift pump?

Where is the FSD?

[BB123]

What's the best way to test the lift pump, I know where it is. And the new fsd has been on the truck about a month and is still on the pump.

[65TD]

Best way is with a gauge between the filter manager and the IP.

Opening the t-valve on the filter manager drain and looking for fuel to come out while engine is under load is good enough.