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.
Press the accelerator pedal all the way to the floor (including kickdown if you have it).
Hold the accelerator pedal down to the floor for 5 seconds and turn the key back to 0.
Now release the accelerator pedal and wait a minute or so before starting your car.
A bunch 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 no time at all.
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