While driving at freway speeds, my truck has started to loose power and run so rough I had to pull over to the side of the road. I looked at my fuel pressure gauge and it read 0. Shut of the truck...restarted and bingo a solid 18-19 PSI. It had done this 3 times now in that last few days. No codes, fuel pump is running fine when checked but when this happens pressure drops to zero on the gauge. Today when it happened at 65 on the freeway, I just popped it in neutral, quickly shut it off and immediately restarted the engine to have it gone and finished driving home normal. Running a Walbro GSL 392. Any ideas?

 

Believe your LP is messing up. Don't know the brand, but have seen vanes collapse for some reason. Can't pump squat when this happens. Restart and O'k till hangs up again.

 

Thats what I am thinking...just wanted to post to see if there was any other possible reason I didn't know about...like maybe a relay or something.
Thanks

 

Sounds like something in tank possible algae growing. The pickup screen isn't that big and blockage will restrict flow. When engine quits blockage moves away from pickup giving flow back to pump. Drop tank and pull the module and take a look.

 

x2 on this and check/replace your fuel filters.

 

BigIron is probably correct. You can check for this by "teeing" a vacuum gauge in the line between the lift pump and the tank. Anything over 2 In Hg vacuum at wide open throttle means a restriction of some sort, probably a plugged in-tank filter. Not a diesel expert but with a 3/8 fuel line on a gas burner, a good system will never exceed 1" Hg.

Over the years I have found a few plastic sandwich bags "sucked" around the in-tank filter too. Mystery as to how they got there.