I've got an '03 MCS that I bought last September. Its got about 90k on the clock and its my daily driver. Anyhow, after the engine is warmed up, and I roll up to a stop light to idle for a minute, there will be a slight stumble in the idle at times. Sometimes it will idle fine for 30 seconds then sound like its running on 3 cylinders. Other times it wont happen at all. I blip the throttle and it goes away. When its got this "stumble" it hasn't ever stalled, though it sounds like its close to it. I just give a quick rev and it seems to clear up. The engine runs perfectly at any rpm and there's never any hesitation. This ONLY happens after I've been driving it for a bit, and a come to a complete stop allowing the engine to idle.

I will fix this issue, but I was hoping that someone had come across this problem before and could direct me in the right direction....

Thanks in advance for any advice.
Josh F.

 

My 2004 MCS does this too. I suspect that it is related to the supercharger pressure bypass valve. Do a search; others have reported the same problem.

 

I have the same issue, although it doesn't do it with any regularity. My car has many mods and since it doesn't stall or ever set the SES light I've decided to ignore it until it gets worse.

My initial guess is that the IAC (Idle Air Control) motor is sticking (if the Mini even uses one). Post back if you figure out what it is.

 

Same thing here... I have read many others have the issue. Its never stalled and I doubt it ever will. The power is always fine at all other RPM levels. It does not happen all the time. It seems to mostly happen in the summer time though...

 

Thanks for the info guys, I didn't realize it was so common or I would have searched before asking.

rough68fish: I was initially taking the same approach, since the SES light has never come on, and its never stalled... I didn't bother with it. I was just wondering if anyone knew, and I'm glad I asked since others have had the problem. For instance I had to drive about 100 miles this morning (travelling for work) and it never did it once. Thats the problem with it, there seems to be no pattern. Ambient temp, driving style, engine temp, etc.. etc.. I cannot "connect the dots" in order to solve the problem.

Thanks again and I'll do a search to see what I come up with.

 

Hey there,

My 04 MCS has done this since new - no ryme or reason to it. According to the dealer the "Official" MINI fix is to just blip the throttle.

They have reprogrammed my ECU several times and never fixed it.

However I did add a Unichip a few months ago.... and it helped ALOT. I have noticed a major reduction in the times this happens with the unichip installed.

It still happens once in a while - but it is very rare now and when it does happen it is alot milder than before - more like a very slight miss.


Good luck