Misfire at 1200rpm

[marinabrid]

Hi all 
Sods law as you think about selling  it starts misbehaving.
Happened with last car wife owned.
ANyway noticed this slight vibration around 1200rpm on tickover, On driving you can feel the engine surge a bit in that low rev range, i know it doesnt use that speed much and soon is gone. but there none the less.
Put on vagcom on measure block 014   ign misfire recognition.   on the boxes as i revved the engine  just as it hit 1200rpm the misfire reognition box activated and   the number of misifres went from 0 to a long number..  when passing through the rpm   it goes back to 0    on repeating   it dooesnt always activate the misfire box, 
no lights on dash and no fault codes so nothing major i think, so thinking it could be the coil packs though i changed these with some europarts ones a couple of years ago along with the plugs. 
any other ideas welcomed

[alial]

hi..have you checked for system air leak?

[marinabrid]

No ,   not being an ace mechanic where would i be looking.

[KingyMAK]

It's fairly easy to check to see if a plug is at fault, just swap it with one from a different cylinder & see if the misfire changes cylinders.
If not, it may be a coil pack or wiring (as they can get brittle and snap inside).

[marinabrid]

got no vagcom readout for which cyl it may be as not fault code come up yet.  i only see it on the measuring blocks 014     then when i rev engine to around 1600 to 1800 rpm  the misfire recognition shows just a series of long numbers   then it goes off,  i have tried changing the coils with one i had spare and still got same result  so will put a fresh set of plugs in and see what happens.    after that  im not sure where to look next.