C180 - 1998 Auto - Random High Rev when stopping

[C180]

My C180 has been randomly revving up around 2000+ rpm especially in the morning when its cold.

The the car keep revving even without pressing the accelarator at traffic light, either with the Drive, Neutral or Parking.
The rev seems to stay constant at that level without any sign to decrease at the normal level.

However, it does always do this all the time. Took the car to my local merc specialist - he did a diagnostic check and no apparent problem found.
MAF was replaced a couple months back, so could not be this.

Any thoughts on this ?

 

[Big_Jon]

Idle control valve?

 

[C180]

Thanks yiddo. I'll check this with my mechanic.
Would this fault not show when the electronic dagnostics was done ?

 

[BlackC55]

It does not have an idle control valve.

Clean the throttle housing 1st then if that does not sort it it may need a new one.

 

[C180]

It does not have an idle control valve.

Clean the throttle housing 1st then if that does not sort it it may need a new one.

Think it needs a new one. Cleaning only seems to work for a few days. Do you know how much will this cost ? Should i go for oem or original ?

 

[lynall]

I always clean throttle plate assys with carb cleaner and an old toothbrush.
The fact that it works when you clean it means you are on the right track.



Lynall