Engine Knocking 92 xj

Curious on were I should start with this knocking noise that seems to be coming from the front of the motor. It can be heard clearly as the engine cranks to start up and a couple times after it's shut off. Also can be heard while running. I've yet to change the plugs or gas, but it worries me that the noise is distinct when turned on and off. If anyone has any suggestions it would be greatly appreciated.

Any luck fixing that knocking?

You posted part of the solution, do a complete tune up on it, plugs, wires, cap and rotor, oil and filter change, new air filter, can of Techron in the tank. Do a top engine cleaning and throttle body cleaning. Also look at your serpentine belt, is there any fraying from it being forced to the front or the back of the pulleys.
Does it do it when it idles ??? If so use a long screwdriver like a stetescope to try to isolate the sound but watch the moving parts or you may end up with the screwdriver thru your head. Im not sure if the 92 had a knock sensor, I think they were on the side of the block under the exhaust manifold. Need to make sure its running right to try to isolate the problem first.. You could also do a pressure test on each cylinder too...