GMScott

I'm placing this in the emergency help board hoping for a quick response. Any help would be greatly appreciated!!

Just developed a very LOUD engine knock. 114k miles. The 2nd lift pump was just replaced after limping home from FL. on an average of 4- 6 lbs. of fuel pressure and now THIS!!

No visible problems, no performance issues, no dip in oil pressure, no elevated temp.

Hard to determine where knock is coming from. Being a backyard gasser mech, I would describe the knock as sounding like a stuck lifter.

Someone told me a bad injector pump could make a similar knocking sound.

Funds are limited as I've been unemployed for over a year so anything I can check myself would be helpful. Up to now truck has been used as very light duty. I had to put it to work to earn it's keep and now this!!

Thanks for your help

RCW

take the time and check the simple things like a small stone in the serpentine belt before looking elsewhere.

If it is not the belt, check the valves to be sure they are properly adjusted.

If the knock continues, I would look to the flex plate on the automatic transmission as a source of knocking if it is loud and consistent.

The injection pump will simply quit before it starts knocking very loudly. You can get an injector rap if an injector is plugged or burned, or if the injection pump has started to disintegrate and plug the injectors. The best way to check for a bad injector on a 24 valve is to use a laser thermometer and read each exhaust port flange at the exhaust manifold. If one is excessively hot or cold, then I would suspect that injector.