2016 CM-S-ALL4 auto.
18.7k miles.
JB+ installed by dealership. Ive never touched or adjusted it.
91 only. Usually shell.

I have a strange studder/hesitation under heavy acceleration between gears while shifting. I.E. if I'm accelerating up a hill or on the highway or passing someone under moderate to heavy pull the engine/tranny seems to studder while shifting between 3-4 gear. Very weird. Any ideas before I bring it to the dealership?
JB+ problem?
Tranny Problem?
Fuel delivery problem?
Electronic Problem?
?
Thanks.

 

I'd be interested to find the culprit. I've been getting a similar studder as well when I pull a bit hard driving in semi-auto and Sport mode.

Essentially, I shift when the gear starts getting a little jerky on the top end. I am seriously hoping it's not a transmission issue.

Stock 2011 CM-S auto, 73.5k miles, 91 only.

 

@croy90 sounds like you are having the same issue I am. I am going to drop mine at the dealership next week (second time) and hopefully they can get to the bottom of it. Not only is in an annoyance its definitely NOT right at all, something is wrong! I feel like its an electronic issue but we shall see.

 

I Had the same thing on both my 2012 and 2016 ALL4S. Once you up the boost using a JB+ or similar you need to regap the plugs to .024. I also used a one heat range colder plug. The higher boost starts to blow out the spark is all I can say.

The JCW models run higher boost and a colder plug.

Ive also found that these cars are very fuel sensitive, not just Octane but brand. For my MIni's they run like crap on Costco 93 which is a top tier fuel. Mine like Shell or Sunoco best. Maybe its the additives I really don't know.

My 2012 is at 80k I bought new and my 2016 is at 19k bought new so I know everything that's been done, fixed etc to these two cars.

 

Sounds like the ole spark plug shudder. Replace your plugs with OEMs and you'll be right.

 

My 2014 Countryman started stuttering about 4 months ago, especially at acceleration. The first trip to the dealer they said nothing was wrong. It got quite a bit worse and when I returned a month ago they replaced the spark plugs and coils and did an injector flush. He runs like brand new now! My only guess about my first trip to the dealer is that it wasn't bad enough to show up on the computer yet.

 

My 08 MCS would do the same thing when going uphill at highway speed and trying to accelerate. It would be like a super knock, a little smoke would pop out the rear and then keep going like nothing happened. It was attributed to carbon build-up in the heads/valves.

 

Update:

I just changed my oil and replaced the spark plugs (way overdue) with BERU OEM's and the high RPM shift studder is gone. Could do the trick for others out there. All in all cost me about $175 w/ labor. I cannot stress this enough, but the car drives better than it ever has (I bought it used with relatively limited maintenance history).

For reference, this is what I use:

Oil: Mobil 1 5W 30 Full Synthetic Oil High Mileage
Filter: OEM Mini Cooper Countryman Engine Oil Filter Kit 11427622446
Plugs: BERU 4 Spark Plugs MINI TURBO N18B16 12122293697

 

Dealership replaced the coils and plugs again. All under warranty. Seemed a little better today. Will update the group...

 

Hey guys! I actually had the same problem with my countryman & it turned out to be the JB+ on mine. As soon as I unplugged the JB+ and cleared my codes using my OBD2 scanner, and my rough idle and shift problem was fixed.

 

@Quintin_Magill, Im curious if my JB+ is causing the studdering issues I am having? My 2016 CMSALL4 is at the dealership for the third time for this issue. They have replaced the plugs twice, and the coils once. Usually drives ok for a couple-few tans of gas then the issue starts again. Im hoping its not the JB+. Did you remove yours entirely or adjust and reinstall? Thanks for any feedback.

 

For me it was the JB+. I completely removed it and sent it back to JB HQ to get it tested, and they found nothing wrong with it. However, when I removed the JB+ and cleared the codes I had no problems and haven’t had any since. I say try removing your JB+ & then clearing the codes, can’t hurt.

 

Did you re-install the JB+ after clearing the codes or are you just going without it? Are you looking at other tuning modules at all?

 

I ended up trying my friends JB+ after and it worked fine. I am considering going for the NM Engineering Power Module next.