I own a 1994 ford flareside with 351windsor, i just recently put in a used fuel pump in the rear tank, and it worked great for about two weeks until i filled both the tanks up completely full and during the week I was running my truck of the rear tank and themn i pulled into a parking lot and was ideling and all of the sudden i see all of this gas shooting out of my front tank through the gas cap so, i first thing i do is turn off my rear tank and switch to to the front tank and wait a while until it stops flowing out of the cap. so i run the front tank till it is about the three quarters mark and then switch back to the rear tank and then there is no problem. Then about a month later i filll the tanks up again and this time i run off the front tank the whole time until it gets in the empty mark. So i switch over to the rear tank and i relized i was getting real crappy gas mileage, and all of the sudden it starts to sputter and i immediatley switch over to the front tank and it regains it's power but to my suprise the front tank was half full when beforee it was empty almost, and the rear tank read empty. I don't know what the problem is I but i could real use some help and if any one has some recall info on it i would realy appreciate it.

 

check with your dealership, there is a recall for a valve between tanks. I don't know but your truck might fall into the recall.

 

the recall is for the check valves on the tanks. they plug into one of the lines off of the tank and prevent fuel from going back in.