S3Kris

Hi guys,
Lately ive noticed a fine soot on the rear of the car, only on the rear. The car is yellow and the soot is black, whilst standing from 1meter away its invisiable but when you wipe a clean hand over the rear of the car you get black dirty marks on your hand which just dusts off after you wipe your hand...

It looks like soot from the exhaust, Im wondering is the car running rich? I'm averaging about 550kms from 55litres of Premium 98RON petrol.

last week the car had a service, the oil was changed and the oilant, oil filter.
The exhaust pipes dont look dirtier than normal but im worried of course?

is this normal operation? id imagine after 1 week of driving it would be pretty dirty....