Power goes down with Fuel gauge

[TKilgore]

When towing, If I get down to 1/4 tank (which I try not to do)there is a definate loss of power.



Normally on flat ground my truck wants to run ~72 while towing and has plenty left. If I let the tank get to 1/4, it will not hold 65mph so I back off to 55 - 60 and find fuel. With full tank, doesn't matter if I shut off or not, get back on Interstate and it has full power again.



I have checked for the rollover plug and don't have one. Is the cap vented. Any ideas?



Thanks

Tom

 

[Thomas]

If it were a venting problem and you can get down to a quarter tank, I think that you would have noticed a collapsed tank by now. Removing and replacing the cap on your quarter-full tank should also give some answers to your venting concerns.



Perhaps it's time to check the lift pump. I imagine it has a harder time supplying the injection pump as tank level drops.

 

[Boldt's Wagon]

Might have an air leak at the 1/4 tank level on the fuel line inside the fuel tank

 

[TKilgore]

lift pump

I replaced my lift pump a few K ago and gauge shows good pressure. Haven't tried the cap thing because I am usually on the interstate and when I stop its for fuel. I really should try it some time. thanks

 

[R.E. Miller]

Don't forget that the hot fuel coming out of your return line is now entering into less fuel which does not offer much in the way of cooling. This should not be too much of a noticable power loss, but I have heard a few truckers say that their power goes down a little when they start getting low on fuel.



Just trying to help



Russell