1988 Jeep Cherokee spark plugs

How about telling us what you changed and how this problem started.

Gotta start with the source of spark as I dont know what you already changed.

Start with the distributor-

If engine was disturbed while distributor was removed, proceed as follows:
Rotate engine until No. 1 cylinder is at TDC compression stroke.
Using a flat blade screwdriver, position oil pump gear so that slot is slightly past the 3 o'clock position.
Position distributor rotor at the 5 o'clock and install distributor on engine block.
When distributor is fully engaged with oil pump gear, rotor should be at the 6 o'clock position.
Align distributor housing to engine block marks made during removal, then install distributor hold down clamp and torque bolt to8 to 10 ft. Lbs.
Note: If crankshaft was rotated after distributor was removed, use the following procedure for installing the distributor.

Remove No. 1 spark plug.
Place finger over No. 1 spark plug hole and rotate the engine crankshaft slowly until compression is felt.
Align the timing index mark on the vibration dampner with 0 °(TDC) on the graduated timing degree scale on the timing gear cover.
Turn the distributor rotor to point between No. 1 and No. 2 spark plug terminals on the distributor cap.
Install the distributor cap and spark plug wires.
Install distributor and connect distributor leads.
Start engine and check timing - set to specifications.

I wouldn't go messing with the distributor right now. There is no reason to disturb that at this point. We need to know just what you have done already and what you are finding.