The CEL on my wife's 2007 Mini Cooper S came on and my OBD stated misfire on cylinder 2. Took the car to a Mini specialist and he replaced the coil pack (they were original). Low mileage car; 58k. The CEL came back on a day later. I switched the coil packs and it was still cylinder 2. I bought 3 more coil packs (Delphi) and replaced them myself. My wife is driving the car again. If the CEL comes back on, is there something else easy that I can check or should I bring it back in for more service? The plugs were new last summer...

 

Did the "MINI Specialist" pull the plugs before replacing the coil, he should have swapped the coils around first to diag that ?

Even seen iridium tipped plugs in your model melt down like a candle increasing spark plug gap to point of misfires. Check the gaps.

 

Thanks. Agreed that he should have switched the coils. As they were the original coils, they needed to be replaced anyway... If the light comes back on again, I'll check the plugs and swap them just to make sure it is not a plug before I bring the car back in...

Being in RI, have you heard of the Minis on Top event in NH? My wife and I are going for the first time in June. Looks really good...

 

+1 The coil swap is the easiest way to tell.


Then go to the plugs , sounds like possible plugs. I have also seen build up on them from non carbon blasted intakes.

 

Looks like cylinder 2 is the problem area here. As Raven said, you can pull out plug 2 and swap it with another one to see if the misfire follows with the plug and starts misfiring in a different cylinder. If it does, it's time for some new plugs. Plugs here if needed: http://www.pelicanparts.com/catalog/..._pg1.htm#item0

If this doesn't fix your issue, report back and let us know.

Also, you're at about the time for a carbon clean up. Have you had this service done yet?

 

Well, it is not the coil packs (replaced all 4) and not the spark plug (did the switch and no change). I had the carbon cleaning done (the walnut shells) by the dealer about 18 months ago... I am bringing it back to the shop that thought it was the coil pack to see what he can do...

 

I'd have them do a compression test to just be safe. I'd also look into the injector as a possible cause as well. Some info here.