2010 Jeep Liberty PO300 and PO306

[EvilEvoIX]

Just got the Miss-fire code, no idea why. Yesterday I drove 300 Miles and all was fine. Today, after a day again of mall shopping style driving, stop and go like, started the car while not completely cold but sitting for an hour, while idling the CEL poops on.

I brought it to Auto Zone and they pulled it and it was PO300 and PO306, should I be concerned? 41,000 miles.

Thanks guys...

 

[tjkj2002]

Change the plugs at 30k like you should have?


Oh and any misfire code is bad,more so for your cats which are expensive.

 

[1BADKJ]

p0300 is a random misfire and p0306 is cylinder misfire #6. Yes it should be a concern. If your check engine light starts flashing that means you could hurt your converters.

 

[EvilEvoIX]

code went away on it's own. The dealer said that when it gets detailed before sale the engine may have gotten wet, particularly the coils so the misfire can be from that. Car drivers beautifully and just got 20MPG on a 600 Mile round trip.

 

[Dave]

Glad the codes went out for you. Had a similar thing happen recently. Was on a little trip and when I got back I gassed up. Then got a MIL (not flashing) and drove the rest of the way home. It ran real smooth just like it did before the MIL. Got in the driveway and was going to hook up the scanner but it was so darn cold that I just did the "key trick" and got a p0304 and said "ooohcrap". I was a little concerned but it was running real smooth. Figured if it was the gas I would have more than a one misfire code plus the P0300 code possibly. Also, I just put a new set of plugs in it when I did my pre-winter service so I thought it might be the coil pak. I was going to switch the #4 and #3 coil packs to see if the code moved to #3 but it was sooooo cold I thought I would give it a couple of running cycles to see if the MIL would go out. On the 3rd cold start (3rd day) no more MIL. No idea what caused it but it hasn't come back. Knockin on wood here. Misfire codes are "hard codes" so I was real concerned. I feel lucky.....

Dave

 

[JeepCoMJ]

isn't this in the wrong subforum? Pretty sure the KJ's didn't go on to 2010. Just sayin.