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Simple. Get a friend to help you. Start with the truck off, and lay down under the truck, with your ear towards the gas tank, preferably the middle-front area. Then, have your friend turn the key to the "run" position. Do NOT try to start it, just turn it to run. When they do that, you should hear a short buzzing sound for 2-3 seconds and then it shut off. No buzzing? Fuel pump isn't working.

If its supplying fuel to the injection system then its working...no supply,,not working

Aside from it working, you need to check that it's developing the right pressure. You'll need to attach a pressure gauge to the schrader port on the fuel rail.

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