electric fuel pump with stock gas tank

I'm sure the lifting may be the issue. I have my external pump mounted in the rear of the tank under the rear tire well. That way it's level with the bottom of the tank and ran a hard line around the driver side to the factory pickup that I modified and added a return line too. The factory pickup supply line 90* up towards the floor out of the tank. I gentle persuaded it to turn towards the drivers rear tire to avoid having to lift the fuel any more than needed.