I own a 2009 MkVi VW Golf 1.4 TSI with a DSG gearbox. It had a major service 2 weeks ago at the local VW dealer. Since then acceleration has felt stodgy and fuel consumption has got worse by about 8%. It feels like they've disturbed the timing, but they say they won't have done anything that would impact the timing. They say they'll carry out a diagnostic check to find the cause, but want to charge me £110.00 to do it. Is it true a major service (65000 miles) would not upset the timing? As this is VW, is it possible they've reset the engine in order to meet emissions requirements and have impacted performance and economy as a result? (this is a petrol engine though). Thanks.