My emmissions warning light has been going on and off periodically for the last few weeks. Also experiencing hesitation as I accelerated.

Got the fault code checked and it is a faulty knock sensor. Don't know how common a fault it is but the guys I have spoken too have never had to replace one.

Anyway got myself a new sensor only £15, but it is buried deep in the engine on the cylinder block. Not too bad on a one or cooper but on the S you need to remove the supercharger to get at it. I'm doing the work myself as at approx 7hrs you would prob be looking at a bill of £500+! Plus I don't like garages touching my car anyway.

So when I find the time to do it I will takes lots of pics for you folks as its quite a major strip down, wish me luck....