Anyone had any issues with timing chain tesioner on there r56. my car is an 07 cooper s with jcw engine tuning kit and has just hit 15000miles. took it to the dealer as fuel econemy dropped from 34 average to 26 ( i do drive it as its ment to be ) suddenly and it was flat spotting and backfiring on overrun and at gearchanges
dealer tested it and it was showing a knock sensor fault. they checked timing and it was out. they reset it and replaced the tesioner with a modified one and performance is better. car is smother and less ticky at idle
anyone else had seen or got this issue. or know if this is the true issue or dealer taking piss with the warrenty?
i personally though it was an injector the fact it was sudden