1988 F150 Lariat XLS Long Bed...

1) with gas in both tanks... if on the front tank, the gas gage registers. if on the real tank, the gas gage does not register (goes to empty).

2) when switch to front tank about about 15 seconds (guess fuel line is empting) truck start bucking and will stop. Then switch back to the rear and truck runs find.


With the fuel pump in the tank, is there a way to be sure the pump is bad and not a bad electrical connection. I have had a few in other places.

 

Go to the plug at pump have someone turn the key on with the switch on that pump to see if you have power going to the pump or you can jumper out the pump relay so that power stays on while you test it.

 

My truck was doing that for a while. Turns out the fuel filter was clogged. With my truck on the back tank it runs awesome and the front tank is a little hesitant to start and take off. Changing the fuel filter did help.

 

Sooo...you had a fuel filter for each tank feed line ??

 

stumped need help. put in new fuel pump on rear. new on in front is not working (thinking bad pump) rear pump will only work with fuel switch placed on front tank. no wires are crossed that we can find. So does the front pump have to be working in order for the switch to work or what do I have here!!