I have a MCS build date June 13, 03. I notice when I first start my MINI after letting in sit for 4+ hours that I will get rough idle. About 5-15 seconds after I start the car the engince becomes rought, the RPMs drop to around 600-800, the car almost dies, the RPMs shoot up to arround 1100-1300, and the car returns to normal. I have had the car actually die on me twice.

I have tried starting the car with and with out the AC on, it doesnt seem to matter. It is not cold out, so that is not the problem.

It also seems to take longer then it should for the motor to start. Instead of the 1-2 times (engine turning over) it should take for a new EFI engine to start it take 2-4 times.

I also believe I have the stumble problem, if that helps. I have searched the boards but really havent found anything that fits exactly with my problem. My dealer is 3 hours away, and it only happens when the motor has had time to cool of, so that would be a waste of my time at the moment.

 

I'm having the same idle / die problem as you describe - just wondering if you ever found out what was causing it?

Mine sometimes will have the rough idle and will die when I let my foot off the gas -- the pattern seems to be related to the engine temperature. Once the car comes up to full operating temp (temp gauge is at half way) the problem goes away.

Haven't taken it to the dealer yet, since it's a fairly intermittent problem. It happened yesterday for the first time in two weeks. I'm hoping to narrow it down myself first.

Any thoughts would be appreciated....

 

My MCS has similar cold start characteristics. Not great sounding until warm imo. Hasn't stalled or stumbled since getting v36 however. I think a uprade if you haven't already is step one.
Certainly shouldn't stall, maybe look for a vacum leak after that. The PCV hose has been updated because of apparent oil saturation allowing to become soft. I hear it sucks itself nearly closed and baloons up under pressue. Heck have the dealer replace it while getting the upgrade. Just to be sure.

 

Did that suddenly start or was it like that from the day you bought the car?
Mine's a 6/03 build...nothing like that happening on mine.

ECU is still running the pre-v36. other than the cold stumble (first engagement
when cold), the car runs fine.

 

Well I have a Mini Cooper, and I believe they do a similar thing.

Ever have an old car without an automatic choke? I just think that the engine management is a bit confused if it is really cold. Normally I find if it is idling below 1000 revs at or just after start up, giving it a little bit of gas pedal, to 2000 rpm for a couple of seconds normally wakes things up, them it will idle at 1100-1300 revs until its warmed up a bit.

 

I took the car in to the dealer yesterday evening, hoping that it could sit overnight and the tech could check it out when it was cold.

The dealer called today and said that they saw the rough idle, but it didn't die. So, they flashed it with V36. I'm to pick it up tomorrow morning after it sits outside again and we'll see what happens. I'm not too optimistic, since it was behaving so consistently bad for me (don't know why they couldn't reproduce it, I can do it every day).