It's a manual. Didn't think to ask about the top of the pistons. I just got it home. They had it for a week (inc the holiday weekend)...several techs drove it, all trying to recreate the issue. None were successful.

I picked it up an hour ago...drove 30 minutes home...and the problem immediately surfaced after the engine was fully warmed and I got off the highway...I got a FLASHING(?...never saw THAT before) check engine light (that then went out after 30 seconds?)...I was in gear, decelerating, going downhill at 30mph when the CEL came on and flashed.

Came to an idle outside the house, rough idle. Read the codes. "cylinder 1 misfire".

Called the garage...they are baffled.

So the garage, who honestly, I thing are rather close to expert on classic mini's and new MINI's, replaced the spark plugs, and then, like I said, couldn't recreate the problem (either before OR after replacing the spark plugs).

They are saying coils are next, $60 each, not much labor. But they admit...they are baffled.

I'm driving it 1000 miles next 2 days...I feel OK about that (not great, but OK) as it runs fine under power...no loss of power or MPG's or codes while running at speed...only pops up decelerating in gear, or at idle.

Yeesh.

 

I am shocked to hear that they would change plugs without even looking at piston tops......and reinstall old coils!!!!!

Perhaps you can take this issue into your own hands. Order up a set of OEM coils and the plastic wiring clips that go on top. Install them yourself and make sure clips are snug.

What the shop should have done instead of wasting a week of your time is monitor the 02 sensors and thermostat with a scanner while the car warmed up. They can data log misfires and look at fuel trims at the same time. Great shops don't waste their labor time or their customers time - they create value and trust by being proactive. They should have also shown you the spark plugs that will illustrate which cylinder is running lean or rich. Now if you go back for coils the original plugs will have been thrown away!

If things escalate beyond the above- a great shop should be able too have a discussion with you about checking and cleaning the VANOS. They should also be able to determine if your thermostat is stuck. At proper temperature, the car has the possibility of readapting and regulating itself.

Do you have someone that can help you? ECS, out motoring,Way and many others list the OEM ignition coils and the special socket for spark plugs. If you are a BMW car club member or an enthusiast, tell your local dealer as many will offer a 20% discount to honor that.

Stay on task the best you can and I am certain that you can yield a more meaningful result than that shop gave you. Best of luck and please post up what you are able to find out.

 

Since I don't know your VIN, I "bingo'd" the options. My choice showed injectors. It's highly unlikely that any of the other N12's don't have injectors, but I'm not about to say they don't.

 

R56devotion...

Thanks for the encouragement. I've actually swapped out an entire motor on a car once (not a MINI)...so I do know my way around, to some extent, under a bonnet.

Maybe yes, I'll do the coils myself.

There's a lot of scattered threads about this problem (runs fine cold, misfires when hot, esp at idle), and not much consensus about what's wrong.

The Vanos gizmos have been mentioned more than once, but one of those times cleaning them did NOT fix the problem.

Do you have a good shop near you? I travel between New Mexico and central/southern California quite a bit, and could stop anywhere in the region to make use of a good shop.