S80 petrol - shudder at idle

[aslan]

Hi all,

My S80 turbo shudders or trembles when it is in idle. It is most noticeable when I'm stopping at the traffic light in D with brakes on. The engine sort of miss but not the point of stalling. Looking at the RPM dial on the instrument cluster, I can't see the RPM dropping.

Under other conditions, eg accelerating, coasting, the shudder does not appear. The engine pulls smoothly and strongly.

Switching off the AC does not have an effect. There are no codes.

I had the car in at the dealer for another issue and at the time it had this symptom but it was not so pronounced. Only an attentive driver would feel it. They did a full diagnostic and everything was ok.

I recently changed the transmission torque mount. The small bushing was completely shot. After a new one was installed, the shudder became more noticeable. I guess the old broken mount was isolating the engine shudder?

Throttle body was recently cleaned. It has new Volvo plugs and new coils.

Any ideas?

Thanks!

[GrahamBrown1]

i could be wrong here, dont have a great deal of experience with the bigger petrol engines but dont these have an electrical idle control valve? this may require cleaning if it was not done with the throttle housing that is.