1993 Jeep Grand Cherokee Laredo Running Really Rough!?

I would double check your firing order first of all, but cars can run rough for hundreds of reasons......dont waste your money throwing parts at it that do not fix it, take it to a reputable shop and have it looked at. Good luck!

Is the check engine light on?

There are so many things it could be, but a few things you might check out... At night in the complete dark, and with the hood raised and the motor running, inspect the spark plug wires and look for an arc. Also make sure all the plug connections are secure- but do that only when the motor is off! ha.

Make sure you have the right wires going to the right spark plugs. The correct firing order is needed for a smooth running vehicle. Was the vehicle running as rough before you changed the wires/rotor cap?

If you are a do-it-yourselfer, I'd recommend getting a professional diagnosis, then do the repairs yourself. You could waste a lot of time and money otherwise.

Some possibility's are

Bad plug wire or wires

Bad distributor cap

Bad vacuum advance module

Cracked or broken vacuum lines

Faulty injector (s)

Bad fuel, water in it

Burnt or cracked valves

Bad timing crankshaft sensor.

Blown or leaking head gasket.

Burned or cracked piston

Those are the most common

I'm guessing that you probably have a rock stuck in there, try driving the Jeep backwards for a bit, and at the same time apply brakes. this should dislodge it. (when doing this the grinding might seem to get worst first before it gets better)sounds like small problem.

have you checked the gap in the plugs.. and the rotor is adjusted right?