MY99. Centre de-cat 3.5" exhaust. K+N air filter.
Superchip

Car usually idles at 600rpm. Lately it's between 800 and 400rpm.
At 800 rpm the cabin shakes quite noticeably.
Of late after a spirited run, the revs fall to 800rpm (and car shakes) before settling at 600rpm.
Also seems to hesitate off boost between 2500+3000rpm when hot.

What is going wrong?
Please not the MAF sensor. Please not.

 

Are you sure your car use to idle at 600rpm? the average is 800 +/-50rpm.
Cant comment on the problem you have but if your worried, get the car down to a dealer/speciallist soonest, and take it easy!!

Tony

 

Yes. Smooth as you like at 600rpm.
Dealer today couldn't feel the vibration (lumpiness) and said they couldn't fault the car.
But on the drive home, stuck in traffic, the vibration was the worst it has ever been.
The thing is, the vibration only appeared after a cambelt change service, and has been growing steadily worse week by week.

I'm confused and worried.