Revs go up and down on their own

[clarky_two]

Whilst idling the engine reves rise to just below 2000rpm, just for about 20 seconds then fall back to 800rpm. This has happened twice now, whist sat in stationary traffic. Any ideas??

Its the 130bhp diesel passat on a 52 plate 89k full service history.

[STEWY L]

Whilst idling the engine reves rise to just below 2000rpm, just for about 20 seconds then fall back to 800rpm. This has happened twice now, whist sat in stationary traffic. Any ideas??
change the cd,and don't tap your feet:biglaugh:
sorry mate, it's a petrol engine i assume?
it could be many things but i would suspect that the throttle body requires
cleaning.
try searching throttle body for more info,
regards,
stewy.

[smiffy vw]

my moms did that some 1 told me it to do with air pipe or air leaking some were and then i was told it wernt it was somet else, jsut leave it :Blush:

[Captain Answer]

my Moms Did That Some 1 Told Me It To Do With Air Pipe Or Air Leaking Some Were And Then I Was Told It Wernt It Was Somet Else, Jsut Leave It :blush:

My-eyes-oh-my-eyes

[audipersempre]

Had similiar on a Rover 820. Check for vacuum leaks or it could be a sensor. Gonna be tough to find I suspect :(