Hi there. I have an 03' cooper S recently seemed to be down on power reaching just 50mph in 3rd gear. I couple of times now on putting my foot down and reving up to say 5k the car has gone into limp mode. I put it in the garage and diagnostics showed nothing. Got it serviced etc, recently had an air filter and seems to be running fine on idol. Has anyone got any ideas what this may be? To sum it up the car feels restricted and then under load seems to hit a limiter of some kind and then go into a limp mode. If i restart the car then its fine again and then the engine light turns its self off.