So i installed a aftermarket 255lph last week, test it, ran fine. Today, drive it for a while, then my cars dies on me. Long story short, I can hear the pump, but im not getting pressure to the engine bay. I opened all the fuel lines at the engine bay, and theyre all dry. But it will get pressure if I drop the tank and leave it on the ground. but as soon as i strap it back in. no more pressure. And yes i have gas in it. Just below the halfway mark.

 

I had a similar problem like this, check to see if the alternator solenoid fuse is blown. It's located under the dash, mine was blown