About 2 weeks ago I was on the motorway and giving it maximum acceleration in 6th gear from 60 to 80mph. Around 75mph the car suddenly lost power for about a second and stopped accelerating with a shudder. After that second it was fine and carried on accelerating as normal. No matter how much I tried by slowing down and speeding up again I couldnt replicate it. Today, the same thing happened again in exactly the same circumstances. Aircon wasnt on and the road was flat and dry. Anybody else experienced this?

Mine did it a couple of times. I took it in and they discovered that the head needed decoking and a new engine block was required.
Three weeks down the line it did it again today. I suspect it is something to do with the notoriously dodgy high pressure fuel pump but getting it to replicate the shudder is almost impossible.

I'm glad you put this thread on as I have had this happen 3 times under the exact same circumstances as you!! The last time was a few days ago and quite aggressive really, I thought about going to mini but couldn't quite explain it properly and I can't replicate it. Do you think this needs reporting to my mini dealer as S8RAH did as that sounds serious! Thanks (cooper s FWD)

Yes! This is exactly what I was going on about in my "Herky-Jerky" thread. The behavior is worse when the A/C compressor is running. In fact, I've only ever experienced it when the A/C is on.

My experience was worse than yours the very first time it happened. I was completely off-throttle coasting down from 65. At around 55 I change lanes and apply pressure to the throttle (not aggressively, mind you). There's a long pause as the car is trying to figure out what to do, and then I was subject to a pretty significant forward-backward jerking motion. The engine was also making a knocking sound (you know, pre-ignition pinging). There was also a fair amount of sooty exhaust coming out the rear. So, I let off the throttle again, re-apply throttle, and all is well.

I personally believe that it's a software issue. I am also unable to reproduce the behavior on demand. In order to avoid the problem altogether, I downshift the transmission myself using the steering wheel thumb control when I feel any sort of hesitation from the car and I'm preparing to accelerate again. I've not experienced the issue since I started doing this. I'm waiting for a software refresh to mysteriously make the problem go away some day.

I've never owned a car that I've had to baby like this one. I suppose it gives the car "character". However, this behavior does make me question the long term reliability of the car. We tend to keep our cars a minimum of 10 years. I am thinking of purchasing an extended warranty for this car based on these recent experiences. This "herky-jerky" BS aside, my wife and I do love the car.

'11 Cooper S Countryman All4

It turns out that this is a common problem. There's a good thread on the subject on the North American Motoring forum titled "Stumble when accelerating?". I can't post the link because I apparently need 15 posts before I'm worthy of such powers.

Cheers

Same here with my Cooper S All 4. Happened 5 times in 4000 miles - impossible to replicate. Been to the dealer who has checked for error codes but none showing. Will just have to live with it for now.

Google THP PCV delete for the fix, the manufacturers are aware now and have offered a solution.

can u confirm that this is the applicable page dave? it appears to suggest that i should be removing a hose and fitting caps made by peugeot. surely that would invalidate my warranty?

http:// www.etuners.gr/en/index.php?s=12&t=299 (http://www.etuners.gr/en/index.php?s=12&t=299)

So would oil need cleaning from somewhere to stop this continuing to happen even once the hose has been removed?

That's the applicable page. If you're in doubt about your warranty, purchase the caps and ask them to fit them, after all, the parts are PSA who designed and built the THP Prince engine.

Oil doesn't need changing and fitting these plugs will stop the ridiculous consumption.

Re: "the car suddenly lost power for about a second and stopped accelerating with a shudder." Had the same problem with our Cooper S Countryman. On the second visit to the dealer they swapped two of the coils over and haven't had the problem since.

Re: "the car suddenly lost power for about a second and stopped accelerating with a shudder." Had the same problem with our Cooper S Countryman. On the second visit to the dealer they swapped two of the coils over and haven't had the problem since.

Hi - thanks for the post. Mine hasn't done it since around 4,000 miles - closing on 7,000 now - but will keep this in mind if it starts again. I have other problems sadly - pinging from rear diff - diff replaced and fine for a few hundred miles and now noise returned. Waiting to drive another All4 from dealer to see if it is any different.

Re: "the car suddenly lost power for about a second and stopped accelerating with a shudder." Had the same problem with our Cooper S Countryman. On the second visit to the dealer they swapped two of the coils over and haven't had the problem since.

Apologies if this is a silly question, but what do you mean by "coils"?

I've had this problem with my Countryman S twice in the last week, exactly the same bit of road, cruising at 40 and then dropping two gears and flooring it to 80. Those are the only two times it's happened in 14 months and 13k miles. It's going into the dealer tomorrow for them to look at an ABS controller problem and will look at this too, it will be interesting to see if they acknowledge it's a known problem.

Hello All,

Those of you who are experiencing stumble issues are not alone. There is a thread over on North American Motoring that deals with this issue in depth. Out of that thread came a reference number for the software update that Mini have developed in order to address the issue -- "SI MI2 02 11". If you are experiencing this issue, please take your vehicle to your Mini Service department and provide them with the reference number "SI MI2 02 11".

After receiving this software update, the engine and transmission my Mini behave so much better now. It's like driving a different car. It drives so much smoother. There's no hint of hesitation or stumble anymore. No jerkiness as you come off the throttle to decelerate. As an added bonus, it seems that gas mileage has improved as well by about 10%. Amazing! I knew that this would eventually come down to a programming issue, but I didn't have the patience or time to be a guinea pig.

Anyway, I hope that this helps others who are experiencing this issue. I am a much happier Mini owner now.

Cheers,
Grat

I have another problem now. When i started the car up from cold this evening the idle was extremely rough to the extent that the rev counter needle was going up and down. It sounded as if it was about to stall but managed to keep going whilst making a metallic clanking noise. I drove it home and it was fine though. Will see what happens tomorrow when its cold again.

I have another problem now. When i started the car up from cold this evening the idle was extremely rough to the extent that the rev counter needle was going up and down. It sounded as if it was about to stall but managed to keep going whilst making a metallic clanking noise. I drove it home and it was fine though. Will see what happens tomorrow when its cold again.

That's pretty "normal" for a Mini. Mine does it all the time. The engine is usually loud when cold and on idle but as mentioned before, also watch out for the death rattle.

Just tried to start it, but first time it coughed and spluttered for a few seconds then died and the A with the circle on it appeared on the dash. Now it wont start at all. Waiting for BMW assist. How fabulous!:angry:

BMW assist finally arrived after a 2 hour wait. He managed to start it but still coughing and spluttering until it warmed up. Hes reset the engine management unit and i have to wait til its gone cold again now to see if it's ok.