hey all, i have a 2002 series 3 gu with 3.0L motor, manual, it had oil leaking from around the seals where the injector lines go into the motor. i put in the mechanic shop to get them replaced, just got home and noticed the motor doesn't shut off straight away when i turn the key off and has a shutter. have had a bit of a read about other with similar problem and got a little confused, just wondering if anyone had any ideas why this is happening. is it something to do with the work i had done or just a coincidence.

a little info on car, only bought 2 weeks ago and noticed the oil leak when i got home with it. car has 230000k's on it. was told by previous owner he had a solid fly wheel recently fitted(i think that's what you call it). starts and runs fine. any input is appreciated. cheers