HELP 98 Cherokee "miss"

Engine RPM related. That can be any number of things.

The problem in the 98 is they got rid of the abiltiy to pull codes with the key on-off-on-off-on trick. It takes a diagnostic tool.

Here is a laundry list.

Bad or failing coil -can cause miss particurally at higher rpm

Bad connectors to the CPS (crankshaft position sensor) -usually when hot, but when the CPS fails your jeep stops running

Bad O2 sensor - Shows up as bad MPG and decrease in power as the engine runs too rich - will also show up as excess carbon on the plugs

Dirty IAP (idle air passage) - rough idle usually is the first indication

Clogged fuel filter - usually shows up as lack of higher rpm power but can cause lean pinging at full throttle.

Since you already did most of the ignition, I'd suggest start by cleaning the connectors (watch you don't get contact cleaner on the paint and use a good dilectric grease to keep the water out.

And clean the idle air passage.

The other thing to do is reset the Jeeps brain. Just pull the battery for 10-15 min. Amazing what that can clear up sometimes.

Dirty TCC connector or TCC starting to go. I fix 42re's on Heeps all the time.