SHHH my jeep will hear you!! engine light woes.......

    My Jeep has been SO good to me and I started talking about how good it's been and it decides it's going to give me trouble. 80,000 hard miles and nothing mechanically but a fan clutch and thermostat. Not the case anymore.


    I get a "Cylinder 4 misfire" and "Multiple misfire" a few days ago when I run the OBD on whatevahs reader. The light was reset then came back on. I have a LITTLE trouble starting it. If i don't let it warm up and I hit the gas it almost begins to loose power. When it's warmed up it seems pretty good on starting, but colds starts are not good.


    I have a 2005 6cyl.


    SO, what can I do to fix the problem and begin to troubleshoot it. I've replaced the spark plugs with the right ones.....is there something I missed? The engine light came on with the other spark plugs and I changed them out to make sure that wasn't the problem.....


    Looking to find out if I can trouble shoot the problem.


    Questions or comments to help figure out the problem??

    How are the idle RPMs at startup (cold and warm)? It's remotely possible that your IAC is getting dirty or the passage in the throttle body is getting clogged, too. Beyond the spark plugs, not sure where to start looking for the misfire. I'm beginning to hate engines right now...

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

    sounds like what mine has been doing. Was in and out of the dealer 6 times for the same thing over the past 2 months. This time is seems it is working fine. They did the following.... carbon soak the motor, replaced fuel injectors, replace the cat system, and replaced the o2 sensors. each time they did something it seemed to work better. Also the hard start that i had was cause by a bad fuel pump (leaking pressure ovenight) was also replaced and fixed that problem. HTH

    When i worked as a tech for jeep dealers we saw these alot. most cases it was caused by excess carbon on the valves. hard start was sometimes caused by the cam postion sensor (formally distributer). Fuel pump or injectors bleeding down was seen also.

    Quote from Rookiejeeper


    When i worked as a tech for jeep dealers we saw these alot. most cases it was caused by excess carbon on the valves. hard start was sometimes caused by the cam postion sensor (formally distributer). Fuel pump or injectors bleeding down was seen also.


    if its carbon, they say the seafoam cleans the carbon out of the engine.. cheap try?

    1997 TJ 4 banger 5 speed, 4.88's, detroit tru track in the front d30, RE 3.5,OME shocks, JKS 1.25" BL, 33" BFG A/T's, Llama bumpers tire carrier, Hi lift

    I just had a similar problem with mine... for a couple of years(didn't drive it much) it would stumble after a heat soak, then throw either misfire on cylinder 2 or a multiple cylinder misfire... after that it progressed to having the computer put it into limp mode after the misfires started (this was only after heat soak cold starts and driving it was fine) last week I finally got a new code which was for the fuel injector on cylinder 2.. I checked the resistance across the leads of the injector and found it was open, where as all 5 others had 13 ohms... swapped the injector to cylinder 1 and got the same misfire and injector code so I replaced the injector and all was well....

    you can use my code reader and multimeter if you need.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

    if you get the code multiple Misfire it useally means a cat is going bad .no power slugish ,what is going on is the cat is breaking inside ,and blocking the exaust from exiting in the right amount this is useally the problem but it can be something else , not a injection problem , them dealers will tell you anything if you do not have a clue ,and bleed you dry , try this take out your 02 sensor and drive it and see if there is a differance in power, wheather you get it back or not , if you do the cat is bad ,try it you have nothing to lose and it will not hurt anything , will sound a little loud but this will tell you wheather or not it is the cat . My thoughts and if you are in N wilm I will put my scanner on it for ya ,no charge of course . then you can get the codes for ya .let me know if you need to know how to get the stubborn 02 sensor out ,

    Quote from ineedabin2


    if you get the code multiple Misfire it useally means a cat is going bad .no power slugish ,what is going on is the cat is breaking inside ,and blocking the exaust from exiting in the right amount this is useally the problem but it can be something else , not a injection problem , them dealers will tell you anything if you do not have a clue ,and bleed you dry , try this take out your 02 sensor and drive it and see if there is a differance in power, wheather you get it back or not , if you do the cat is bad ,try it you have nothing to lose and it will not hurt anything , will sound a little loud but this will tell you wheather or not it is the cat . My thoughts and if you are in N wilm I will put my scanner on it for ya ,no charge of course . then you can get the codes for ya .let me know if you need to know how to get the stubborn 02 sensor out ,


    Late model TJ's have 2 cats and 4 O2 sensors, 2 precat, 2 after.

    so your reccoemending that i take out all 4 02 sensors and ride, and see if there is a different in power. if there is a difference it means what?


    I've run with Jerry's scanner and I'll do it again. It said misfire on cylinder 4 and multiple cylinder misfire.

    I dealt with the same 2 codes, and i would reset it and the codes would always return, but nothing seemed wrong except my idle was a little low, but not really noticeable. Then one day, I took it to my cousins auto shop class, his instructor did a compression test, and then noticed my head had been cracked. :bang:

    he has the Champion 4412 plugs.

    Jerry / Whatevah

    2020 Gladiator Mojave - 33" Falken mud tires, LoD side steps, Zroadz bed rack, Quadratec QRC winch bumper, Superwinch EPi 9.0, Kleinn on-board air, Kleinn air horns, lots of lights, Yaesu ham radio with GPS tracker.

    Gone- 2012 JK Rubicon with stuff. Long gone- Long-arm 2001 Cherokee with stuff.

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