Towbar 2

I have had this 87 long bed I-6 for 3 months now and have a peculiar problem with it: The rear tank can have plenty of fuel in it but the engine will begin to sputter like it is starving, I switch to the front tank, no problem. Later, I will switch back to the rear tank and it may run great all day of for a few miles before doing the same thing as before. Has anyone any experience with this? Any luck at figuring out what the trouble is? I'd appreciate some help with this. Thanks in advance.

Manuellabour247

Have you checked the fuel filters?

Just call me Sean

iTrader: (1)

The pump is going bad.

Towbar 2

I guess the pump could be going bad, but I have no trouble at all running the front tank only. It is when the rear tank is used that it will act like it is starving. And like I said, I can switch to the front, run awhile and then switch to the rear and run a few minutes or several hours. I will double check the filters, I really wasn't aware that there were more than one. Thanks for the input.

Just call me Sean

iTrader: (1)

There is only one filter, there are three fuel pumps. The rear one is going bad, or the tank selector valve is sticking.

Manuellabour247

Hm, that's a new one for me. Guess my buddies truck had 2 more inline filters installed by somebody after the fact. They were old and FoMoCo stamped, just figured they came from the factory that way. Thanks for the knowledge.

Chris_1

iTrader: (1)

Sounds like the low pressure pickup pump in the rear tank is possibly dying - or you have a bad connection that switches over or doesn't switch over depending on what it feels like doing. Pulling the box off is sometimes a major pain, but in your case it would allow you to not only change the pump easily if necessary but also get a real good look at your wiring and hoses. If you do change the pump and you take the box off, I'd recommend you do both pumps while you're in there, as after all - it is an 87 (high quality pumps will save going back to do it again)