My 89 F150 has a troublesome problem that I don't know how to diagnose. 90% of the time, it runs great. About once every two months or so, I fill up and it dies within a block or two. No matter how much I crank it over, it will not start back up. However, if I put a bottle of fuel dryer in the tank and wait about 10 minutes, it starts running great again.

This has happened several times under various conditions and with different grades of fuel. The only thing I suspect is that my truck is somehow picky about the formula of gas that a particular station might sell. I've never had this problem running on gas from my normal station, but when I fill up somewhere else, there's a good chance that the truck will die. For instance, this weekend, my father-in-law (93F150) and I filled up at the same station at the same time. My truck died and his was fine.

I have dual tanks, but I'm only using the rear and it has a new fuel pump. The hoses & filter were replaced about a year ago, so I don't suspect that they're the problem. The only thing I can think of is injectors. The engine was rebuilt just before I bought the truck, but I don't know if the injectors were replaced. Should I get them checked out?

 

No, it sounds coincidental. Ford truck engines just aren't built in a way that would only allow them to run on a certain blend of gas, and gas stations don't sell blends that won't run in any engine. Next time it dies, just open the gas cap, but don't pour anything in. Then see if it starts. Also, check the vacuum line coming off the fuel pressure regulator for presence of fuel vapor or liquid. See how the exhaust smells, and test the coil for spark.