Hi,i have been having a few problems with my 2.9 s80,started with a missfire which i traced to No 6 coil pack so fitted a new one and thats now ok,but i have an idle speed problem.
When you release the throttle in park the idle speed drops to about 500rpm before it then picks up and idles fine but sometimes it does it for a few seconds idling up and down before it settles,,,,ANY IDEAS.

 

Last time I had rough idle the mechanic in "stealership" cleaned ETM and PCV system and it helped. I bet you just need to clean ETM.

 

Thanks i will try this,will keep this post informed.