Need some help/advice. My '99 A6 1.8T has developed a misfire and loss of power above 5K revs. The car has 67K on the clock. It's recently been serviced and all Audi parts were used. I don't have access to VAG.COM but I have a OBD11 scan tool and this is showing no faults. Before I bring it to the dealer to get the diagnostics checked is there anything obvious such as 1) Coil packs do they fail and can I check them with a multimeter 2) Fuel filter, how often does this need replacing 3) MAF, I know my brothers passat diesel has problems with these but are the petrol ones more reliable. If there is anything I am missing, if so help would be appreciated.