Ford Repair: Fuel system, Fuel Pump, poor mileage, fuel pumps

Question
I have a 1990 Ford E-150 Club Wagon, It has two gas tanks, while running on the rear gas tank it pumps gas into the front tank, I have been told by the local Ford Dealer that both fuel pumps need to be replaced, they say the check valves are in the pumps and the front check valve checks out as bad,the rear check valve is slow to react. The van still runs fine, If you run down the front tank first. Do I have to replace both pumps or can just replace the front one. the motor is a 302, automatic transmission. Also the vehicle has aprox 111,000 miles on it, around 87,000 miles the motor was rebuilt I had a towing cam put in it ever since then It has had poor mileage, it went from 15-18 MPG to 10-13 MPG, Can I do anything about this without changing the cam?  This is a one Family Van, I hate to give up on this Van. Thank You

Answer
Hello and thanks for the question...I'll try to help.
I would go back to Ford and ask about the dual fuel tank recall and see if your van is involved in it. It doesn't require the replacement of the pumps........just an addition of check valves in the fuel lines.
As far as the cam and such...get the fuel pump fixed first.....I think you'll notice an improvement on the mileage.
Erik