Code P0300, running badly and misfiring badly like gunshot?

VICKSAVAGE

MEMBER
1998 CHEVROLET 1500
5.7L
V8
4WD
AUTOMATIC
217,000 MILES

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?

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
42,840 POSTS

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.

Images (Click to make bigger)