02 missing #4 cylinder

[ChristianKline]

hey guys in the last week my kj has been acting funny, i was riding through town and i stopped at a stoplight, when i took off you could tell there was a cylinder missing, but after it got to higher rpm it seemed to stop, and it did not do it after that while i was driving, but just yesterday while driving to work i got on it to pass and it missed again and the check engine light started flashing then stayed on constantly, so when i came back to town after work i took it to o reillys and they read the trouble code and it said the #4 cylinder was missing and it was either wiring or the spark plug, but after searching around and talking to some guys it seems like it could be a little more complicated such as low compression or a fuel problem, just wanted to see what your opinions were, because i dont want to take it to a dealer ( low on cash ) i want to try to do the cheaper alternative instead of a mechanic who fixes everything but what is needed,

thanks guys, christian

:whymewhyme:

 

[jaybic]

Hello to you all! I am new here and this is my very first post. Anyway, funny you post this because I have the same 02 Liberty and it is doing essentially the same thing.....missing on #4 cylinder. for me its usually right on a cold(like hasnt ran all day or overnight) start. I bought it used last month with 97,000 miles on in for 5000.00 and its in immaculate condition but this concerns me. I just changed the plugs out on it to Champion Platinums gapped at .40ths and hope that might take care of it but when I started it, it still seemed a little bit rough and it seemed that there was a very minor but noticeable extra little "shake" or shiver to the engine every so often but it was not constant.....any ideas on what this might be or where I should go next. heck, i dont know, maybe its normal to have that little shiver to it....Im lost....it also seems like the fuel mileage is down....I live here in SE MN and a full tank gets me about 250-275 miles...maybe its all in my head but what kinda mpg are you guys and gals getting when your KJ is running like it should? I just thought maybe it was another symptom of an issue......

anyway, thanks to anyone with any ideas and great forum you folks got here!!!!!

Jamie

 

[SabaII]

ChristianKline, you want to check the plug first on that hole. If that seems fine try swapping coils between #2 and #4. If the code follows you know its the coil, if not then try swapping injectors between #2 and #4. Again if the code follows you have an injector issue. If not then you have to start looking further. As you are doing this you should be paying attention to the connectors. Make sure they are not corroded or have any burnt terminals. Try those things first and report back.

Jamie, I would switch back to Copper plugs. I personally think the NGK V-powers run nice in our Liberty's. A dirty IAC will cause these to run a little rough at idle. I know mine does and I know I need to replace it but am living with it. I am in Roch as well so shoot me a pm if you wanna meet up sometime I can take a quick look at things.

 

[ChristianKline]

hey guys well today i am thrilled, i went out and bought 6 new spark plugs threw them in and it solved all my problems, i reset the computer and the engine never gave me a fit, i tried to get it to miss i could not, sabaII thanks for your help but when i took out my #4 you could see how bad the plug was, it was cracked and firing straight into the block, so i knew exactly then what it was,

THANKS GUYS!!!

 

[SabaII]

hey guys well today i am thrilled, i went out and bought 6 new spark plugs threw them in and it solved all my problems, i reset the computer and the engine never gave me a fit, i tried to get it to miss i could not, sabaII thanks for your help but when i took out my #4 you could see how bad the plug was, it was cracked and firing straight into the block, so i knew exactly then what it was,

THANKS GUYS!!!

Good to hear.

 

[jaybic]

Hey all,

well, as per my post above, I replace the plugs(have not yet switched back to copper as was suggested and thought my miss had gone away but it returned. both times it was on a cold start shortly after having rained(damp, humid air?). on both occasions the engine light was flashing so I shut it off and restarted it and then it ran fine and the flashing engine light went to a solid(not flashing) engine light. should I start changing out the coil packs next? ideas anyone?????

Thanks again for your time!

Jamie

 

[SabaII]

ChristianKline, you want to check the plug first on that hole. If that seems fine try swapping coils between #2 and #4. If the code follows you know its the coil, if not then try swapping injectors between #2 and #4. Again if the code follows you have an injector issue. If not then you have to start looking further. As you are doing this you should be paying attention to the connectors. Make sure they are not corroded or have any burnt terminals. Try those things first and report back.

Jamie, I would switch back to Copper plugs. I personally think the NGK V-powers run nice in our Liberty's. A dirty IAC will cause these to run a little rough at idle. I know mine does and I know I need to replace it but am living with it. I am in Roch as well so shoot me a pm if you wanna meet up sometime I can take a quick look at things.

Read that again.

 

[jaybic]

Thanks Chris, I did and I guess thats where I go now I guess....honestly I am not too much in the know on this sort of stuff so here goes the first stupid question.....which is number 4 and number 2 cylinders? I would assume that all 02 Libertys have their cylinders numbered the same Yes?

Thanks again guys.....

 

[SabaII]

6 5
4 3
2 1

Front of engine

 

[jaybic]

Thanks again, I shall go switch the #2 and #4 right now and see if the miss transfers to the #2. If so, I should have located the suspect component I think...

thanks again!

 

[jaybic]

Well, I havent posted in a while but I did end up switching the coilpack on #4 with #1(does it have to be #2?) and I still got a misfire on #4 cylinder so I am kinda lost. it is still pretty much on a cold start but I am wondering all sorts of stuff. am I not holding the key long enough for that one lazy cylinder to start? an injector dirty or malfunctioning? I have seen other posts on here saying new plugs fixed it, a new battery fixed it(something about the battery not getting enough juice to the computer) and in the same thread, something about carbon deposits messing up the valves and needing a complete rebuild. also had intake leak thrown at me for a possible cause....does anyone know of any 2002 Jeep Liberty service bulletins or chronic problems or heard any potential solutions for this? I have pretty much resigned myself to seeing the flashing light come on, shutting it off immediatly and restarting it(the engine light is no longer flashing but is on)and driving it and pestering my mechanic to shut off the code every other week and I know hes gonna get tired of that.....anyone got any ideas, I am all ears and thanks much for your time ladies and gents...

Jamie

 

[Billwill]

Well, I havent posted in a while but I did end up switching the coilpack on #4 with #1(does it have to be #2?) and I still got a misfire on #4 cylinder so I am kinda lost. it is still pretty much on a cold start but I am wondering all sorts of stuff. am I not holding the key long enough for that one lazy cylinder to start? an injector dirty or malfunctioning? I have seen other posts on here saying new plugs fixed it, a new battery fixed it(something about the battery not getting enough juice to the computer) and in the same thread, something about carbon deposits messing up the valves and needing a complete rebuild. also had intake leak thrown at me for a possible cause....does anyone know of any 2002 Jeep Liberty service bulletins or chronic problems or heard any potential solutions for this? I have pretty much resigned myself to seeing the flashing light come on, shutting it off immediatly and restarting it(the engine light is no longer flashing but is on)and driving it and pestering my mechanic to shut off the code every other week and I know hes gonna get tired of that.....anyone got any ideas, I am all ears and thanks much for your time ladies and gents...

Jamie

Have you swapped out the #4 injector yet?

 

[bigd]

whats your idle at when you start it cold, mine had a missfire at cold start when my IAC valve was bad. You can try to clean it first and your tb at the same time free and worth a shot.