Just 350 miles into ownership of my base Cooper, the engine will not idle smoothly. Jumps up and down between 500rpm and 1200 rpm. Runs rough and then stalls. Under power on the road it's fine, but the idle stuff happens warm or cold. Anyone else have same problem ?

 

I haven't had any problems , but you might want call your dealership and tell them about it.

 

I had it happen three or four times this summer. In all instances it never threw a fault code. Try this. Whenever it would happen I would shut the car off take the key fob out, wait 30 seconds then reinsert and start the car. The problem would disappear and the car would run like nothing was wrong. Also it only occurred when I was running errands around town making multiple stops in successive short trips (high heat load), usually after the third or fourth stop. i was suspecting an intermittent idle sensor failure (mass flow sensor, throttle position sensor, or throttle poistion switch) that cleared itself by restarting the car or a computer problem either from sensor input or internal.

Had roadside assistance tow it 90 miles twice. Dealer kept it both times for a week, trying to reproduce it and couldn't. i had several candidates of problems in the idle control system that I wanted them to possibly replace. Without witnessing the problem or having a fault code they wouldn't replace anything. I ran this all the way through miniusa, and then mini corporate. Got mini engineering involved and they said it was a fuel system problem. I doubted that answer at first as I was using a top tier fuel already.

Miniusa sent me 3 qts of BMW fuel system cleaner, to use one every 3,000 miles. The dealer told me to switch to Shell. I switched to shell and used one of the fuel system cleaners. I haven't had the problem since. I could possibly have had a sensor fouled by a bad batch of gas, even from top tier brand that I was using. That was either the problem or now that its cooled off it is 'hidden' to reappear next summer.

Don't take anything I said here as a complaint. Both the dealer and mini were very helpful in helping me 'hopefully' resolve this.

Let me know if yours throws a fault code, what may be causing it, and what your dealer says and does about it.

 

At just 350 miles, I'm sure you are still on your first tank. It could just be a bad batch of gasoline. I would dump a bottle of fuel treatment in it and fill up with premium from a busy name-brand station and see what happens. Regardless, you should have it checked out....especially if this is a new car and under warranty.

Good luck.

 

Thank you very much glangford and Fastlane. I will give your suggestions a try. Much obliged.

 

Skip the additive. It'll just muck with the trim sensor, smell bad, and confuse the dealership if you have to bring it in.
The rest of Fastlane's suggestion is good.

 

The OBC is telling me "CC ID 031". Any clues before I take to dealer ?

 

No, but take it in. Something is obviously wrong. Look on the bright side, at least it threw a code so they have something to go on. In my case it did not throw a code so it was wait till failure or for it to clear itself. Hopefully it was in my case just a fuel issue. Please let me know when you find out.

 

Service Dept. says problem caused by "Vent leak". Oil fill cap was loose. This sounds a bit out there, but I know this dealer's staff to be top notch. Hard to believe a loose oil cap could cause such an engine problem.