I have a 1996 F-150 4.9L with dual tanks. The engine runs good on the front tank, no problems. When I'm going down the road and switch to the rear tank it bogs down for a second or two and then normally runs OK. Although there has been times where after driving for a while it really bogged down where I had to switch back to the front tank. It is always hard starting on the rear tank too and usually I just switch over to the front tank to start it. It also seems to siphon gas from the front tank back to the rear tank. I was sure at one time I had nearly run the gas out of the rear tank because I was going to have someone look at it and then when I went to the gas station one day to put a few gallons into the rear tank, to my surprise it was just about completely full! Does it sound like the rear pump needs replacing? This has actually been going on for over a year. Most of the time I've just been using the front tank. Thank you, Bruce

 

Yep, sounds like you need a new rear pump. I had the same problem (though the opposite, my front pump was bad, and my rear was good. My rear tank was filling the front) and a new fuel pump took care of the problem.

 

Heya Bruce,
Your question is one that pertains more to the body of the truck than the engine. Maybe post your question here?

1987 - 1996 F150 & Larger F-Series Trucks - Ford Truck Enthusiasts Forums

 

OK, thanks, I'll do that to see if there are any other opinions.