Car='06 MCS (BRG but I'm sure that has nothing to do with subject) box stock except for JCW strut bar, EBC Green, Panasport FS16 & Goodyear F1 GSD3 with ~6000miles. I have no problem with acceleration from standing start -- low, medium and high throttle -- all smooth & strong through the gears. The prob is when I'm cruising at ~70mph and a low load is experienced either via incline or throttle. I get a stumbling -- sort of breaking up -- definitely not smooth. More throttle lessens the stumble -- heavy throttle pretty much eliminates it. This happens when AC is on or off -- no diff. Naturally, I'm taking it in but was interested to see if anyone has/had same issue and/or has any thoughts/knowledge. Thanks

 

How low of a load? What's the Tac at?

 

Well, cruising at ~70mph is ~3000rpm -- then the low load comes in the form of a gentle hill or wanting to slowly increase speed -- and stumble happens.

 

Try a fresh tank of gas, in case that's the issue ...

 

Sounds like the dreaded "yo-yo" to me as discussed ad nauseum in every MINI forum (the car stumbles or yo-yo's at no load around 3000 rpm, most noticable in 1st and 2nd gear). :impatient

 

Had the wife's out for breakin road trips this weekend. Same deal in all gears. Starts around 2700 and continues to 3200 when trying to maintain current speed in current gear. Let up and it goes away. Give it more and it goes away.

thanks big daddy for the pointer to the other posts.

 

thanks to all for responses -- esp. Big Daddy - I found The Yo-Yo Chronicles...I'll post what the dealer thinks/says/does next week after I take it in...ok, so Mr Service Writer I'm here to have you fix my Yo-Yo...

 

I've experienced the same since day 1. I really notice it going up a slight incline at around 3000 rpm. I've noticed it other times also, and always right around 3000.

 

I've had this problem too...

What fixed it was the MTH ECU remap and (mostly) DetroitTuned bypass valve.

 

to 'gt6' -- yup, as you describe it, we share the same prob-b-b-b-blematic stumb-b-b-ble

to 'DarkMiniCooperS' -- thanks for the details -- I'll share the info with techs at my dealer as a fix for same prob in an '03