Ok so I get a random misfire in my 98 cherokee mileage is 216400. I just changed the plugs, wires, cap, rotor about 6 months ago. The misfire has only shown up with in the last few weeks. I have swapped plugs 1,2 wires 1,4 and still comes up on number 1 no change always that cylinder. So I hook up my souls edge to see if there is anything on troubleshooter. The first thing that pops up is a TSB that says if no cause of misfire can be found may need revised valve spring. I tried looking in to the TSB from other forums on a google search. Supposedly the oe spring are too weak. Also I will have a slight hesitation then it's like a turbo kicks in and she really starts to move. Looking to see if anyone has come crossed this problem before and what fixed yourproblem, if it where the spring or something else.

Little more info on the xj.
1998
5-speed
3inch lift (for now)
33x12.50x15
3.55

 

Check bottom of wire harness for chafed wires, fire wall to motor, back by the valve cover. Could be killing an injector. It can rub through on the weld seam of the fire wall. I had this problem with two 98s.

 

Do you have a Link for a wiring digram. I don't have access to all data anymore I work in a school bus shop now. But will check this weekend.

 

No I don't, the wires are color coded so you shouldn't have a problem putting them back together. If that's the problem.

 

You have to do a compression check on all cylinders then remove the valve cover and inspect the valve springs - especially #1 springs.

 

In my experience, whenever people said, "It's not the fuel injector", it turned out to be the fuel injector.

You easily test this by swapping the #1 fuel injector with another and seeing if the problem follows the injector.