I bought a 2007 Audi A3 TDI automatic 170 5dr S-line with full electric pack from a garage in December and after a few weeks I started experiencing issues when starting from cold in the morning whereby the car would judder and rattle for about 5 seconds or so. After returning the car back to the garage a diagnostic test was carried out only to come back with no issues and was told that it's probably just one of the glow plugs and therefore would have to get worse before further investigation. Apparently it's a characteristic of the engine according to the technician?!? Being the second A3 with same engine, and never encountering this problem I find this hard to believe. Any ideas what the problem could be please anyone. The car a full service history with 68,000 miles on the clock.