This information is well known on BMW and Merc forums. A friend of mine recently bought a BMW
and mentioned this procedure so I thought I would give it a go. I do a lot of slow runs on 50mph
roads every night to work and noticed the car had become a bit sluggish. It was worth a try.
I am convinced that it made a difference, it made the throttle a bit more responsive and there was
a touch more power. Don't take my word for it, it's free to try so give it a go and see what you think.
Ideally it should be be performed every few months, it only takes a few minutes.
Throttle Body Reset
Insert key and turn to position 1 so the electrics are on but the engine is turned off.
Conclusion
A lot of people have tried the procedure and they have all said they have noticed a difference.
If it is real or a placebo it doesn't really matter as it costs nothing and takes almost no time at all.
Enjoy.