I have a 1987 f150 2wd with a 5.0, I filled up both tanks last week and kept the switch on the front tank until today. I'm not sure what's up because I went close to 360 miles on my front tank--don't think this is true. I switched to my back tank after putting some emergency fuel in the front tank, and probably drove about 20 miles before running out. I switched to my front tank and it seemed to be fine. If anyone could help me understand that would be awesome, thanks.

 

Some of the trucks have a problem with fuel flowing between the two tanks.

 

Kinda what I was thinking, do you know much about it? Thanks