Code P0300, running badly and misfiring badly like gunshot?

1998 CHEVROLET 1500

217,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC

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My truck was running fine then water pump when out so I changed the water pump and I always had a hard time getting my truck to start, so I changed the fuel pump as well. now everything out back together now truck it running like badly and misfiring. I changed crank, cam, distributors, injectors, knocker switch, fuel filter another fuel pump, new spark plugs and wires. now I have a new motor to set in my truck will that fix my problem or I’m just wasting my time?

Nov 14, 2022 at 4:10 AM

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I would check the fuel pressure and if okay, the Spider Injector in these trucks was a problem. here is a guide to help you run the test with instructions below to replace the injectors in case you need it:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Pressure 55-60 PSI
Open Throttle 66 PSI

We should run the codes as well to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

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Nov 14, 2022 at 9:32 AM