North American Motoring - 09 R55S frying coils.

A little bit-o-history, at about 60K I done the timing chain, carbon removal via walnut blasting, new plugs. My son works for Advance Auto and I had him get the Denso brand plugs because I have had them in my 08 base for about a year or so and everything has been fine. I noticed once I had completed the work that I thought the car was a bit sluggish but wrote it off to being the difference between having a base and a S.

After about 3000 miles on those new plugs I accelerated hard one day in Sport mode only to have a misfire show up on #3 not sure why but limped it back home to find the coil was bad.

I replaced all four with the set from my 2010 S and it ran fine.

A couple days later again under hard acceleration on the interstate to pass someone it fried another coil this time on #2 again I was in Sport mode.

Looking back I recall he had issues finding the right Denso branded plugs, so I looked into it further only to find from Denso they don't list a plug for the N14 only the N12 in those years so I switched back to the NGK plugs it had in it when I got it and took it for a test drive... OMG the pep I thought it was missing was back so I figured I had the problem solved. Only to find a couple days later it fried the third coil this time I was not in Sport mode but again still under hard acceleration. This time around I wondered if the retarded intake code it also listed was a cause not a symptom.

So now here I am to see if anybody has any possible insight into my issue because I only have one borrowed coil left I know I will eventually have to buy new coils for one of the two because I have 5 left of the 8 coils I started with. I wonder if all coils I have are weak due to running with what I now think are the wrong plugs, I know shame on me for not insuring they were right.

I can update later today with plug part numbers. :impatient: