Engine revving high when idle

[cclassjo]

Two days ago I noticed the car was revving higher than usual when idle and was revving up and down without any pressure on gas pedal, no higher than 1500 rpm, a day later the engine diagnostic lamp lit up on the dash. I intend to get it checked out tomorrow, however in the meantime should I stop driving the car? Oh its a C Class Coupe C200 Petrol, 2003 / 53.

Also any recommendations for a decent independent specialist in Heathrow / West London area?

 

[Parrot of Doom]

I don't know if theres one on that engine, but a similar problem on my TVR was caused by a dirty stepper motor, and an air leak on the plenum.