My sons Mini which is around 10 years old. Starts fine and runs fine but occasionally the engine judders as if it misses a beat for a couple of seconds. Its a lot worse when you are going up a hill and it judders every few seconds before you get to the top then its fine and only happens every 15 mins or so after that? Is it a fuel or spark plug problem or what else ? many thanks
After fitting new coil packs and spark plugs at a cost of £150 the car was still the same! In the end it was a £21.00 cam sensor...