Oil, oil filter and other fluids still get changed regularly as per service schedule (for time elapsed) and the car is started at least once a week for around 10 minutes, normally driven forward and backward in the driveway for a couple of metres. The car was running fine without the noticeable 'tink, tink' noise last week it was only this week (on the week end just past) that I heard this noise, which lead me to the aging fuel as a possible cause.