having trouble my truck runs great when it is cold lots of power all is just fine but after it warms up real good it sputers spits and dies it will restart but no power at all , it will idle juist fine I had lots of codes so I cleared them and let it run in the drive way untill it warmed up and it sputered spit and died then I checked the codes again and I only had code 12 i disconected the fule line to the lift pump and it is working I dont have a pursure gage to test it with and I dont know where the t-valve is also I replaced the fule filter and the pmd made no diffierence I keep telling myself that I would have needed one soon anyhow. :eek:
Im starting to get short on funds I cant afford many more guesses. if any one has some idea' I woud be most greatfule

Try diagnostic checklist.

Looking at signature line of 10% soy oil, may be giving you some issues.... Are you heating the fuel?

Are you running one tank only, or a two tank system?

Check fuel cap for tank vacuum.

May also have a fuel line leak as some have reported in the last few weeks on your vintage. Look under FAQ's under fuel leaks, the link is in there.

I知 not sure about a vacuum in my fuel tank as I haven稚 really gotten it to run long enough to be sure.

I mix the fuel in an auxiliary fuel tank that came with the truck then I pump it through a filter into my main fuel tank. I have been running this for about 5 months and my truck has run better and gotten better milage than just regular fuel. I hope its not the cause of my problim, I have read that if you use too much soy oil it can cause the paper in the fule filtor to swell and clog but that is the only side effect that I have found. so far.

I found the T valve and put a gage on I get about 6 pounds but no volume I changed the fuel filter again. Still no change. I put on a new lift pump no change. so I put back the old one I disconnected the supply line from the lift pump and I知 only getting a trickle of fuel I tried attaching a peace of hose and start a siphon but I only get a trickle of fuel I tried using a hand vacuum pump the kind you use to bleed the brakes with and still it took a lot of vacuum to get any fuel I blew air back into the tank than tried again with the vacuum pump but still not much volume and a lot of vacuum to get just a little fuel. I知 thinking that I have some kind of clog in my fuel tank but I hate to drop the tank I may try the fuel tank from a boat just to see if it solves my problem. I知 fairly certain that I知 on the right track, thanks for all your help I will let you know what I find. And If anyone thinks I知 barking up the wrong tree,,, or just barking mad. Let me know.

is your lift pump getting enough voltage thru the ops switch? might try installing a relay to run the pump.

iirc one of the guys said there is a small screen in the lift pump.

The filter sock in the tank is probably plugged\collapsed - pull the gage sender module to check.

The filter sock in the tank is probably plugged\collapsed - pull the gage sender module to check.

Explain how this is done please.

I believe it requires doing bench presses with your fuel tank...

Either drop tank or unbolt bed. If you have a bed.