I have an automatic 2003 silverado 5.3 that stopped running. It had air and spark, but no fuel pressure so i decided to replace the fuel pump. Installed the new pump, but there's still no pressure. The new pump required me to re-wire on a new electrical connector. I believe i did that correctly since the gas gauge works and when i turn the key on, the pump hums. When I have the fuel lines disconnected from the pump and turn the key, the pump hums but nothing comes out at all. The tank is half full.