Okay I will try to explain this the best I can without sounding like a total Idoit. I recently posted questions about the bad fuel mileage I was getting, on the heels of that I installed an extra fuel tank in my truck which required me to install a small Aux. fuel pump. Prior to this I was getting 12. 5 mpg pulling an unloaded trailer. While on a trip on Wed. I started to run low on fuel so I flipped the switch for the Aux. fuel pump, to make a long story short I forgot about it and before I knew it the tank was under alot of pressure and fuel was leaking out. The strange part is that I noticed my fuel mileage went up to and stayed around 14. 5mpg when the tank was under pressure like that. I tought I was nuts so today I watched it alot closer and tried it again and the same thing happen when the tank got to the pressure that it was leaking. Any clue??? and yes I did take my medication, ha, ha