hi, every time i change gear (up) i get a noise that is very similar to the old ignintion pinking noise from my old mk2 fiesta many years ago, also i have like a bang noise eveytime i stop ,ie after driving the car when its ticking over the bang only happens once every time, but happens every time i stop and tick over, engine code is AZJ so it says on the boot sticker, any ideas, kinda hoping someone has come across this or something similar before.

car is mk4 2.0 gti,