this jeep started running rough a few days ago and found the #2 cylinder was misfiring. it was due for its regular service, so i changed the oil/filter, plugs, plug wires, distributor cap, and rotor. i made a run down the road with it after all that was changed and it ran great. the next morning on the way to town, it started all over again. i checked plugs and found the #2 cylinder was still misfiring. the #2 plug was alittle black and not as wet as i thought it should've been. i pulled fuel injectors/fuel rail and cleaned(found some dirty/rusty crap). i didn't put the injectors back in the same order, and the #2 cylinder still misfires. anybody have any good thoughts???

 

either a short to that injector or bad cps

 

For a single cylinder misfire, you must concentrate on everything related to that cylinder.

1. Plug (you changed that)
2. Plug wire (you changed that)
3. Distributor cap (you changed that)
4. Injector (you swapped that) But you should use a noid light to ensure that injector is firing.....

After verifying that #2 cylinder injector is firing is performing a compression test. Gotta be sure that this problem isn't internal. Can't ignore this possibility. How many miles on this engine?

Test all cylinders with a good quality gauge and see what you get.

The compression spec. for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

Good luck and post back what you find!

 

also check for vacuum leaks in the num2 intake runner

 

that plug may be fowling quick do to that cylinder say small gasket leak which is y it will be good for a day or so then fowl id say u have head problems gasket and check head if you kno its a good plug and the wires and cap