I've got an 88 F-150 with 300 and dual tanks. I have the sending unit problem where the gas gauge stays at full till a 1/4 tank. It's my work truck so I $5 the truck to death.(meaning 5 in gas) I do this so I know approximately when I need gas. Well since I do, I rarely use the rear tank. When I first bought the truck 3 years ago, I filled both tanks so I could get an idea of gas mileage. I ran the front tank out and then switched to the back. I decided to go to Norwalk Raceway Park (just to watch)for their Halloween Classics in Ohio. I started down and when I got about half way there the gas gauge moved to empty. I just figured it finally let go because it was bad. Not to long after that the truck started to sputter then quit. I knew I couldn't be out of gas. I tried to start it and it sputtered and quit again. I luckily had a gas can so I started to head to the gas station about 2 miles back.(ohio turnpike)Then I thought I might try the front tank. I tried and it started up after a few cranks. I decided to try to make it to the gas station, which wasn't for another 10 miles or so. It made it there and when I tried to fill up the tank, only 10 dollars would go in(the front tank). I thought this to be my error, but I tried again after a couple years. I put $10 in the back tank, and ran the front completely out. I started to drive on the back tank for about 20 miles and there she went, sputtered and quit. I again switched to the front and was able to drive another 50-60 miles on that tank. ???????????? ??????????? I don't know.

 

Do you have a low pressure pump in that back tank? If you do, it could be going out - runs a little, then conks out when you put any load on it. Use the front tank if that works just fine, and save your $.