Won't start

[BAT]

My 99 Yukon won't start. Turn the key, had power, just chugs away and won't start. If I pound the gas tank a little it will start. Fuel filter, relay, fuel pump???? Any ideas.

[GM-Tech]

Smacking the fuel tank to get a vehicle with a bad pump started is an old trick we use in service to save having to push one into the shop.

 

I'd say if it doesn't start, and you bang on the tank and it does, you need a pump.