hey guys, just bought an 01 XJ 127,000 on the clock with the 4.0, took it to e-check the other day, passed with flying colors and once i restarted to leave e-check the thing stumbled like it ran through roof deep water and took a gulp and i got a flashing cyl. 3 misfire code on the way home.

once i removed the coil and pulled all the plugs i noticed the first plug closest to the radiator was slightly bent on the electrode end, not smashed into it just had the gap closed up pretty good its the only one doing it . I went to the parts house bought a new set of champion platinums, gapped them and threw them in only to have the same problem at initial start up with yet another cyl. 3 misfire code pulled plugs and coil again to see the same problem same cylinder.


As of writing theres no knocking tapping or any other strange noise, just sounds like a normal 4.0 its got a definite dead cylinder (horrible gas milage, stumble on acceleration, miss at idle) just looking for some best guesses i've already tried putting some marvel mystery oil in that cylinder just to try and get rid of any mysterious carbon deposits on the center of the piston (if only i were so lucky) but no change i'm starting to think i got a lemon with a bad bottom end.


any thoughts???

 

how is the compression in that cylinder and do you have a probe or any friends with one so you can see if the plug is contacting something in the cylinder or something.

 

well havent got that far yet, i've got 3 other cars to finish so i can pay down some bills but i've told myself friday is jeep day lol

compression seems good about 140 on a lukewarm (160 degrees) motor.

i tried the magnetic screwdriver trick as soon as i saw that first bent electrode and got some small pieces of rust most likely from pulling the plug out but nothing huge.


i really dont want to pull this bottom end apart lol

 

that sucks i know how it is though i get stuck working on my wife's car her mom's car and her sisters car and they always forget to pay me for the parts and i just get tired of working on every thing else beside mine then when i do work on mine i am so tired of car stuff that i don't want to do it some times but if i don't who will my wife and her mom or sister no likely. sorry just ranting a little

 

dont apologize for the rant buddy, you quoting a scene from my life.



except for the part when you get asked "why do I need this 50 dollar master cylinder, the brakes still work" haha

 

The problem would be easy if there was some noise but seems baffling with no noise. Are you sure you got the proper plugs. Maybe a plug that is a tad shorter will work and that is the number one cylinder so it makes no sense to get a #3 misfire code. You may have two problems. A plug that is being hit and a possible defective coil pack on the #3 cylinder. JMHO. I am no late model expert.

 

whats the number on the plugs they gave you? I mean the big long wierd Champion #, Like RCxxYC...

 

glad to know i am not the only auto slave around here

 

could be detonation........i would flip the coil rail around if possible and swap the injectors with another cylinder.......see if the problem changes to the cylinder you swapped with.

 

the coil cant be rotated but you could try moving the injectors

 

well i pulled it all apart today, got some spare time finally.

still the same thing, umber one plug is pretty carboned up but that'll happen when the gap is like .10 lol

got the borescope in there and there was a few pieces of carbon in there but nothing else that i could see so i got all that out and put some regular
champions in there so i'll drive around on those for a while and see if i get the same problem.

misfire codes are most likely from the injectors, i only get that code after a short trip, wait about a half hour and restart runs like crap and gets a flashing check engine light

i did however notice that the only injectors that are missing their heat wrap are 3 and 5, and wouldnt ya know it those are the codes i get all the time so i'll try to find those at a junkyard or something.


i'll keep ya'll posted on the plug situation though, thanks for the help.

 

ooooh and bowtieguy, i work at the parts store and checked the plugs like 90 times to make sure i didnt screw up lol