Hey everyone. So, on Tuesday morning my 07 MCS threw a "misfire on cylinder 2" code. I just bought the car 2 weeks ago, and had been driving that entire time with no codes.

New NGK spark plugs are on the way (since it was my first initial thought) - reason I believe is because it sputters a little at very low speeds (~35mph)? BUT, being a new MINI owner, what do I know?

Yesterday, the code disappeared. I hadn't changed anything, or driven any different .. it just disappeared.

Any thoughts on this? I'm already aware there are quite a few things that could cause a "misfire on cylinder 2" code, what I haven't heard of yet is a code just disappearing. I'll change the plugs anyways though, but I thought this was odd.

 

What's the mileage and have you had a carbon cleaning? Carbon build-up can cause misfiring.

 

Sorry for not adding that .. it has 53k. I myself, have not checked for carbon build-up, but will be doing so when the plugs are changed on Tuesday.

If it has been done prior to the 2 weeks that I have owned it, I am really not sure.

 

I have had this happen on what I consider to be a tank of bad gas. Once that gas was gone, so was the problem.

Good luck.

 

I also purchased a 07 MCS in March and I have just done a carbon cleaning at my dealer ($800). It was causing pre-ignition or bad miss-fires sometimes three in a row with a loss in power, now that I had the cleaning done it's night and day of a difference in overall performance. My intake runners and valves looked pretty bad for only 49K. I can here the pressurized intake whoosh every time I step on it, a sound that I never heard before the walnut blasting!!

 

@Systemlord, thanks for sharing! It looks like I'll be doing the carbon cleaning as well if the plugs don't fix the issue. I just bought the car 3 weeks ago and with the extended warranty, I think I have to wait at least 90 days before being able to take it in? That I need to double check. I'm certainly anxious to have the car up and running smoothly!

 

Update: Changed out the plugs earlier this week and so far, so good! Runs smooth, no more hesitation or stuttering at low speeds. I'll continue the rest of my preventative maintenance this week.

 

You'll want to do the walnut blasting to clean the carbon from the intake port as well. Changing the plugs fixes only part of the issue. At 47k, mine looked pretty bad:

https://www.northamericanmotoring.co...ec-tuning.html

 

I saw that thread yesterday, pretty disgusting how bad it was. I will definitely be looking into doing this.

 

I would not jump onto the "carbon build up" wagon just yet.

Swap the coil from #2 to cyl to another plug and see if code follows.

Could just be bad plug coil.

 

The code is very intermittent. I bought the car and then drove it for 2 weeks, about 500 miles before the code appeared, then disappeared 2 days later. Did the plugs anyways, it runs smoother and there isn't any of that sputtering .. but I am HOPING that the code doesn't reappear later. Of course, only time will tell.

 

Much to my dismay, the "Misfire on cyl 2" code appeared again at 55k miles. I had not gotten around to doing the carbon cleaning that people had mentioned. Recently did a seafoam treatment. Wasn't expecting to notice a change with that, and I don't.

However, I swapped the coil from 2 to 3, and then cleared the code. After getting in 18 miles of driving, the exact same code appeared again - misfire on cylinder 2.

Plugs are new. Coils were switched. Code didn't follow. Any ideas? Due to a hectic work schedule, it will be just over a week before I can get my car into a dealer for testing.

 

Let me tell you for the most part my backfiring and misfiring is almost completely gone from having the carbon cleaning! You'll notice that your low end torque and overall quick pickup increases quite a bit after the carbon cleaning. I can now launch hard and get my tires to chirp and spin a little on dry *** fault in first gear, before the cleaning that wasn't possible!

I believe my misfiring issues is the result of two faulty components, of course the carbon buildup and perhaps the HPFP or O2 sensor. Something is causing my MCS to run lean at times, installing my AEM CAI is proof of that! Even more air equals more misfires as my fuel ratio is off even more with an increase of air volume. Installing back my stock intake proved the decreasing the intensity of the misfires or knock.

 

Thanks for your insight. Went ahead and scheduled an appointment with the MINI dealership to have it looked at along with the other few things .. brake light on, sputtering, plus the new timing chain service campaign. Figure if the cars going to be there, might as well have them look at that too! ughh. I just want to get in at least 1000 miles without issues!