Scenic Revving

[freccle]

I have a 1998 Renault Scenic Alize 1600.
It's started revving to up to 4000revs of its own accord when idling,
without any acceleration. It used to just do it when hot, now it's all the time
The local garage says it could be the lamder sensor but when it's
disconnected, it still happens.
anyone any ideas?

 

[^neo^]

Lambda sensor should only kick in when the engine is upto temperature so i would go for the engine coolant temp sensor or the throttle position sensor.

Have you had it plugged in to a fault code reader? (take most of the guessing out of whats wrong!)