Just a thought.
Turned out to be a mucky Air Mass Sensor in the intake ducting.
After the main dealer failed to identify the problem and I spent £140 at the specialists - plugs etc. (It's only done 16k!) I thought of the oil on me K&N filter. Maybe it's coming adrift and contaminating the sensor.
£1.26 for a bottle of Meths and £6.99 for a set of 'security' allen bits and she's off like the clappers again.
Merry Christmas.

 

What sort of misfire was it, a general one or a once every now and a gain type ?

 

where did u get the allen bolts and did u wipe the maf or just spray it