I removed my dfr and bench tested it. When I apply pressure to one of the supply lines I get a little pressure out of the other line. Which is why I believe the rear tank is filling up the front. I was wondering if I could put a check valve in the lines before the reservoir to fix the problem.
86 F150 302. I posted here because there are more people here with the efi 302's

 

I believe that model resrevior had a filter in it, maybe the filter is clogged

 

I am going to have to put this one back on for a while at least so a new filter wouldn't hurt anything.

 

Some great info from Steve83: '84-89 Fuel Reservoirs pictures | SuperMotors.net

 

Yeah I already have that link pulled in another window.