Ok, This is My Problem...

I own a 1997 Dodge Ram, Magnum 8, 5.2 liter. My truck will only start if I turn the key and press on the gas at the same time. I turn the key and the engine starts or it seems as it's going to start but then it dies out when I let go of the gas pedal. It'll remain on as long as a continue pressing the gas pedal. What could it be? The fuel pump? The battery works fine.

Also, is it true or just a myth that if you let you gas tank to almost hit empty before you fill it up, the fuel pump or filter gets dirty and will need replacing soon?

Thank you.

Throttle position sensor probably.