I have an 89 F250, 6 cyl (4.9L (i think), standard trans. It has two gas tanks. It has a switch on the dash to switch between the front and rear tank. The truck runs great off the front tank, but NOT the rear tank. I did some research and learned this year/model truck had a recall years ago for a condition that would somehow cause an overfill condition where the gas from the front tank would be returned to the rear tank, and cause the tank filler tube to fill, then when the rear gas cap was taken off, gas would spill out of the rear tank. I do not believe my truck ever received the recall repair, but the dealer told me it had.
Anyway, when I try to run my truck from the rear tank it begins to sputter and die out as if there was no gas. However, it will at times run for quite a while before this happens. And the gas gauge in the rear tank never seems to show less gas. But the front tank, even when I am not running off the front tank, is using gas. So I think the "dual fuel resovoir" or whatever the recall was, was never completed and is contributing to the problem.
So I will be running off the rear tank and all is fine. Then the truck will begin to die out, sputter, and will die (as if there is no gas), if I do not immediately switch to the front tank. If I do switch to the front tank, it will run fine. If I then switch to the rear tank, it will run fine for a short time and then the same thing will happen.
I have spent a lot of money having fuel filters, high and low pressure fuel pumps, etc changed. I even drained the rear gas tank and put in new gas thinking maybe the gas had been in there so long the gas was bad. I added some gas additive and it did run very well for a week or so. But like I said, the gas never seems to go down in the rear tank. Anyway, I am clueless at this point and hope you can help. Thank you