hi i have a a3 tdi sport 110bhp when i started it it misfired then loads of blue smoke and a flashing glow plug light ive replaced the glow plugs and it seems to be running fine glow plug light comes on as normal with ignition then goes out as normal i start the car and it runs fine after about 30 seconds the glow plug light starts to flash car still running fine anyone have any idears what to try thank you mark