I have a 2000 hyundai elantra (127k miles) and it won't start. I just got gas in it yesterday. I drove it 2 times (short trips) since the gas and then parked it for the night. I suspect the fuel pump. I don't hear it when I turn the key on. the engine turns over but won't catch. I had fuel filter changed 22k ago. plugs and wires replaced at same time. Where is the relay for this? Is it under the hood in the black box? any other ideas. HELP