Cylinder #3 Misfire STILL!!!!

[Jeremy Cryer]

I have a 2001 Grand Chreokee 4.0Cyl.

Wife ran it alomost out of gas about 2 weeks ago,
since then it been running REALLY bad.

Beening showing codes of p0300,p0303,p0304 and p1285.

Replaced coil pack, plugs,both top side O2 sensors, #3 injector, fuel filter.
Replaced the #3 just today and after driving it about 30 mins, same problem arose with the P0303 code.

At my wits end on what else could be wrong!!!!

PLease give ANY advice that could HELP!!!!

[jdl]

Some dealerships are doing valve jobs to get rid of misfires on this vehicle. Carbon build-up can be an issue? The pcm may shut down injector/s to save the cat. I can't tell much from here. Do a compression test.

[dalet]

worked at dodge chrys. jeep ram dealer for years. the 4.0 did have issues with carbon build up on valves. usually when vehicle is operated on short low speed driving. low speed drives would not allow the valves to rotate. this condition can be intermittent. recomend compression test. this may or may not reveal a leaking valve. if compression test is low you have your diagnosis. if compression is good you may have to remove the valve spring and maually rotate the valves.sometimes a good combustion chamber cleaner may help. that is the easy repair if it works.