Over the weekend, I let my mechanic friend take my '03 mcs out for a spin. We tooled around for a short while, letting things get up to temp. With a running start in 1st at around 20mph, he went WOT to about 6k, shifted to 2nd, WOT and stumble (!!). The car hesitated for about 1 second, producing no power.

My first reaction was to believe he was doing something 'wrong'. Hard to believe given his background. So I had him pull over, got into the driver's seat and preceded to 'show him how it's done'. From a running start at about 15mph, went WOT to about 6250, shifted to 2nd, WOT and stumble.

I could not believe it. I picked this car up with 25k miles on it about 5 weeks ago and have had zero mechanical problems since replacing the power steering pump. I tried the same launch 3 more times with 2 more stumbles and one success (varying my shift timing between 5500 and 6500 rpms).

We stopped for a moment, and I remembered reading about the starting procedure. Someone on this board suggested that you should let the car fully complete it's diagnostic tests before turning the engine over. The poster mentioned that many problems disappear with the proper starting procedure. I always do this when I start the car, but didn't think much of it when my friend turned the key all the way over in one fell swoop.

Having re-started the car 'properly', I tried to reproduce the stumble, but could not. In 3 days of driving I have not been able to reproduce the stumble.


Has anyone else experienced this shifting into 2nd?


Perhaps separately, the throttle response seems a bit sluggish since things have started warming up (approximately 20-25 degrees warmer in the last 4 weeks). I've stalled 3 times in the last week from a dead stop. I'm giving it the same gas and clutch action as I always do, but the throttle seems to hesitate for the briefest moment. I'm starting to see the same effect when I blurp the throttle in a heel-toe downshift. The blurps will occasionally either 'miss' or lag the pedal action just enough to miss the sweet spot. I don't believe it's my technique. Everything was buttery smooth until the weather started to change.

Maybe it's time for an ECU update and/or CAI?

 

actually my 03 mcs had the stumble...what it is when MINI did the emissions recall it reprogrammed the computer to take the excess fuel from its normal direction which is to the evap canister and out and sends it into the chamber so basically its a mini engine flooding...when my car was re-registered in indiana i had the local dealer fix the little issue...but the 03's had a problem that something like a issue with vacuum yo-yo...i just ordered myself a DT BPV so well see if that helps!

 

you say the dealer fixed the 'little' issue. what did the dealer do?

 

To simplify my question for everyone. Is my stumble in 2nd gear the same stumble everyone else mentions in 1st?

I've never experienced the full stumble when starting in 1st from a dead stop. I have experienced a slight lag in throttle response when starting from 1st, and when trying to blurp the throttle in a downshift. These symptoms were most noticeable yesterday, when it was 71 and very humid. Is that normal? Are there steps I can take to reduce/eliminate these symptoms?

 

It is probably the Traction control. If you shift hard enough to break traction going into 2nd, the ACS will kick in. ACS will cut the throttle until you regain traction. Watch for a yellow triangle light in the bottom center of your speedo the next time this happens and that will tell you that ACS is taking over.

 

+1

 

+2

happens to me in third sometimes

 

my 03 mcs stumbles too in the bottom of second...and its not the traction control. is there a fix?

 

It appears that it was, in fact, my traction control. I had the chance to take a closer look today, and I can reliably reproduce the scenario. Every time it 'stumbled' the ACS light was on.

Solution: turn off ACS