Preface:
A couple of months ago whilst cruising down the hwy with the cruise control set to 75mph, I needed to accelerate in order to pass slower moving traffic. I got up to about 85mph and let off the gas. But the car continued to accelerate to near 135 mph (!). Pushing the clutch in slowed the car momentarily. As soon as I let off the clutch, the car gradually continued to accelerate. Hit the clutch+ brakes to slow the car worked fine but the same results.
Killing the cruise control button was unresponsive but I did manage to clutch, brake, downshift, regain speed and coast the Mini exist off the interstate. I ran an OBDII scan/ revealing a malfunction fault with the cruise control. Cleared the code and all was right with the world again.

Recently cruising down the interstate with the cruise control set to a desired speed (eg: 70mph) 6th gear,; I've begun to notice that the car will slowly but gradually increase in speed - upto 80mph (if I'm not paying attention). Although this time pressing the clutch or brake will slow the car and re-set/cancel the cruise control.
No faults this time.
Any idea what I might be looking at here? - gas pedal(drive by wire)? Throttle body? BCM damage? Cruise button itself?
I have no idea.
The issue only happens on occasion.

 

can't say I even have a good guess.

what code did you see? might be a good starting place. might not.

I'd bet its happened on other gen1 minis. you can't be the first, can you?

 

The fault code I got after the first crazy incident :
0568. DME: CRUISE CONTROL, 'adjust' signal - malfunction.
No codes and no crazy acceleration since then. Currently, randomly, Just a slow gradual increase in speed with cruise control set. Nothing too crazy.

 

crazy indeed. search did not turn up any hits. I guess I might have a guess if I had a better understanding of how the system worked

 

^^^ me too = totally clueless =

 

Do you have LED Brake light/Taillight Mods?

Those will make cruise control act funny cause of resistance.

You can also take the car out of 6th gear and CC will not work in the future, as it only works in 6th gear IIRC.

 

Interesting.
The only LED bulbs I have on the entire Mini are; front DRL and custom modded rear fog lights in the rear bumper grilles.
Actually, cruise control works in 4th, 5th and 6th. (at least it does on my '04 pre-facelift R53), Never really tried or had a reason to cruise control in 2nd, 3thd or 4th...
except maybe passing through no man's land Oklahoma...(speed traps every 3mi).

 

My initial suspicion would be the switch on the steering wheel or associated wiring/clockspring.

 

You know @deepgrey , I believe your suspicions may be onto something... (much more plausible than mine; "my Mini is possessed")... Although I spend an inordinate amount of time, everyday, trying to keep my Mini clean inside and out - Keeping the amount dust and dirt out of my car is almost futile. Point being: It seems absolutely possible that dirt may have made its way into the steering wheel (cruise)buttons to be causing some of the weirdness. I say this, due to the fact that since I've been out here in the desert; dirt has made its way (a couple of times) into the flat tire reset button. This caused the button to jam, as a result triggering the flat tire and triangle lights on the dash. Since I couldn't understand why/ extinguish the lights by hitting the re-set button, It took me a while to finally figure out that the button was stuck. Removed the button, took it apart and cleaned out the dirt that was stuck within the groove of the button.

Good call. I'll have to investigate how to disassemble the control buttons on the steering wheel if it keeps acting up.
Thanks!