Yesterday on the way to a dyno day I was cruising along and all of the sudden the truck just started poppin and rattling. The pedal got very hard. So i pull over and the it starts to idle fine but it wont go past 2300rpm. So i get to the dyno hook a pressure gauge up to it and it wa reading around 10psi at idle and revving it up. We changed the O/V and it went up to a constant 15psi. So conclusion was that it was the lift pump. The valve and gauge were gunracer1's so i gave those back.

So last night i put a new LP on go for a drive and it would rev up better but popping at at around 2800rpm. Pull it back in the shop and rigged up a fuel pressure system but my prob is my gauge only goes to 15psi and it would peg it. then this morning I went out and it said 12 psi idle and would bounce back and forth about 5psi while revving it. So I stretched the O/V to .5 it was at .4 No change in pressure it just ticks now. then driving down the highway today it did the same thing except this time it died. It fired right back up and would rev up to 2800 but still popping. I changed the fuel filter about 2k ago. Sorry for long post but its got me really confused tommorrow i will get a bigger gauge and see if it changes any. Corey

 

Sounds like your shutdown solenoid isn't lifting all the way.
Remove and clean it, don't replace it.
The way to check the lift pump once you get a bigger pressure gauge is to pinch the rubber return line with pliers to block the flow, engine idling, gauge should shoot up over 50 psi instantly.

 

Ok finally got a correct gauge on it. I reads 17 at idle and it drops a little when you rev it. But while drivin it its about 15 the rapidly starts it descent down to 0psi by 2krpm.

 

man does this sound familiar. you have to be sucking air somewhere or your rubber lines are sucking into a pinch point. but i have heard of the pick up lines getting cracks in them also with age.

 

Sounds like a fuel restriction. Clogged heater or tank filter or kinked line.
An air leak causes hard starting and miss, didn't sound like you were experiencing those.

 

Thanks looks like Ill be covered in diesel all night tonight tryin to hunt this prob down. I dont think that its the tank filter because I cleaned it when I did the sending unit about 15k ago but who knows Ill save that for last. And its not an air leak cuz it starts right up maybe crankin for 2 sec with no pedal at all.