hi all cut a long story short! my bmw when i brought it had not had a service for 40,000miles and 4 years!!!! now since having it she gives a sharp jolt sometimes and starts miss firing (i thought this was just cause she needs a service!) took her into my mates garage today and we: changed spark plugs (bosh super 4) oil oil filter, fuel filter, done engine flush cleaned throttle body (was quiet bad) after all that took her up road and my god she feels like a new car!!! got power back and its loads more responsive! well so i thought!!! took it to the shops 10 min ago and she gave a sharp jolt and started missing again am i right in thinking that 1 of the coils could have a fault or be on its way out?? cheers