Cylinder 2 mis-fire code, yet no loss of power/rough idle....?

[Kyle7R]

Looking for some insight before I dive in and start replacing parts unnecessarily; my '09 JK has just a tad over 38k on the clock, it does not see regular road duty due to me working from home quite a bit and having a plethora of company vehicles available for me to bring home (Thanks AT&T ).

Making the most of my most recent 3 day weekend, I took the Jeep out Monday to run some errands, and get the oil changed as it was due; while I was out the check engine light popped on, I had just gotten fuel on Saturday and thought maybe I'd left the gas cap loose as it has happened before. Tightened it when I got to Home Depot, and after leaving the code did not clear. I had the guy read the code prior to changing the fluids and he let me know it was reading a mis-fire on cylinder 2, asked if I had experienced any rough idle or loss of power, which I have not, and still haven't.

He cleared the code, finished the rest of the maintenance and off I went, wondering if it would return. I got it out of the garage and took it around the block Monday morning and the light returned, same code. I figure to start with plugs/wires at least, yet nothing I have found says they need to be replaced anywhere near 40k miles, that they should last to 80k or maybe even 100k before needing serviced.

Any insight to where I should start, or specifics I should look through? I drove it again today to the office, still not experiencing any rough idle, loss of power, knocking noises, gas smell, or smoke of any sort; if there were no light I would not even think twice about anything going on.

Oh, and also I seemed to have thrown a sticky weight and have an awesome little shimmy around 40-50MPH:bleh:. Any shop recommendations in the Houston area that would do a solid balance on some 35's nearing the end of their life cycle :brows:

 

[WJCO]

An 09 with that many miles may be part of your issue. Vehicles that are driven less tend to get light fuel varnish build up on valves causing them to stick or allow carbon build up. I would replace your fuel filter no matter what just for general maintenance and a fuel injection service or decarb may not be a bad idea. You could swap the #2 wire with another equal length wire or swap plugs just to see if the misfire follows another cylinder just to eliminate that as a possible cause. Obviously, the above info are just suggestions, but you are right, that low of mileage, none of those things are recommended for replacement yet. If this were my Jeep, I would start with those things.

 

[Kyle7R]

An 09 with that many miles may be part of your issue. Vehicles that are driven less tend to get light fuel varnish build up on valves causing them to stick or allow carbon build up. I would replace your fuel filter no matter what just for general maintenance and a fuel injection service or decarb may not be a bad idea. You could swap the #2 wire with another equal length wire or swap plugs just to see if the misfire follows another cylinder just to eliminate that as a possible cause. Obviously, the above info are just suggestions, but you are right, that low of mileage, none of those things are recommended for replacement yet. If this were my Jeep, I would start with those things.

Thanks for the response and suggestions, I had a feeling that it sitting for extended time periods probably wasn't helping. I added some fuel injector cleaner today, and will see if that works. But I also wanted to pull the plug on the cylinder that was throwing the code to check for any signs of fluid or damage, and when I pulled on the wire boot, the wire snapped in two. I pulled another boot/wire just to compare and it came out with no issues. I have picked up replacement wires and a new set of plugs (when in Rome, right?) I am hoping that the plug wire had a short/damage in it causing the error, there's no reason it should have snapped out of its connection that easily.

 

[seanb123]

Thanks for the response and suggestions, I had a feeling that it sitting for extended time periods probably wasn't helping. I added some fuel injector cleaner today, and will see if that works. But I also wanted to pull the plug on the cylinder that was throwing the code to check for any signs of fluid or damage, and when I pulled on the wire boot, the wire snapped in two. I pulled another boot/wire just to compare and it came out with no issues. I have picked up replacement wires and a new set of plugs (when in Rome, right?) I am hoping that the plug wire had a short/damage in it causing the error, there's no reason it should have snapped out of its connection that easily.

That's a good idea I'd give it a good seafoam treatment while you're at it.

 

[WJCO]

Hopefully that simple fix will be the issue.

Thanks for the response and suggestions, I had a feeling that it sitting for extended time periods probably wasn't helping. I added some fuel injector cleaner today, and will see if that works. But I also wanted to pull the plug on the cylinder that was throwing the code to check for any signs of fluid or damage, and when I pulled on the wire boot, the wire snapped in two. I pulled another boot/wire just to compare and it came out with no issues. I have picked up replacement wires and a new set of plugs (when in Rome, right?) I am hoping that the plug wire had a short/damage in it causing the error, there's no reason it should have snapped out of its connection that easily.

 

[Kyle7R]

That's a good idea I'd give it a good seafoam treatment while you're at it.

I actually had a can of sea foam in my hand at the auto parts store and psyched myself out of it.

Just dump the whole thing in with a full tank like everything else, or try some of the other sea foam methods?

Update:swapped wires and plugs for cylinders 2 and 4, cleared the code and went for a quick 10-15 minute drive. Revved pretty high shifting through every gear, laying into the throttle and no light yet.

Will replace the other plugs/wires this weekend at the latest, once I acquire a flex adapter for my socket, three busted knuckles in two plugs is enough!

 

[seanb123]

I actually had a can of sea foam in my hand at the auto parts store and psyched myself out of it.

Just dump the whole thing in with a full tank like everything else, or try some of the other sea foam methods?

Update:swapped wires and plugs for cylinders 2 and 4, cleared the code and went for a quick 10-15 minute drive. Revved pretty high shifting through every gear, laying into the throttle and no light yet.

Will replace the other plugs/wires this weekend at the latest, once I acquire a flex adapter for my socket, three busted knuckles in two plugs is enough!

I prefer the break booster best method for me. But in the tank helps too

 

[Kyle7R]

Update: it's been over a week (and nearly a full tank of gas) but since replacing that plug and wire then resetting the computer I have had no more appearances by the check engine light :knock on wood:

Now to replace the rest of the plugs/wires so everything is the same age [emoji106]

 

[WJCO]

Good to hear. Good luck.