There is a knocking sound coming from the engine and i do not know what it is? is a bad oil pump, flexplate or a piston knocking how do i tell?

 

A broken flexplate is usually at low rpms and disappears a piston would be there all the time I never heard a oil pump knock but maybe...

 

First of all. What kind of vehicle, engine and year? You need to put all of that info in all of your post that you need advice for. Plus we need more info on the knock you are having. Is it constant, on cold start, warm start, does it sound like it's coming from the lower end. These questions need to be answered before any one can even begain to try to help.

 

it is a 91 cherokee 4.0l I6 with the high output engine. The knocking gets worse as it heats up. i do not notice it when driving. i can not tell where it is coming from.