Misfire Problem - Not your usual, please help!!

[zippy!]

This isn't your usual coil pack or spark plug problem, this is something a little more in depth. Basically I have a misfire on cylinder #1, it only happens at idle and its not the injector, spark plug or coil pack as all three have been swapped about.

If you run the misfire counter in VAGCOM you can see it only happens to cylinder #1, hold the revs and it doesn't occur but let it drop back to idle and it starts counting again.

The car runs and drives perfectly fine, pulls hard no loss in performance and still retains an average MPG. The only way you can tell is by the movement on the engine and the exhaust tone (hear a slight 'psst' in between the usual tone).

I'm at a loss to what it may be so please help, if you have any ideas no matter how daft they sound post them.

Thank you!!

 

[ibizacupra]

done a leakdown test on that cylinder? physical popping from leaky valve...?

 

[ibizacupra]

wiring to the coils not fritzed (burnt & breaking down)?
{wild guess}

 

[Beaker™]

I'm right in thinking if it was cracked head / piston / valve that it'd also suffer running problems higher up the rev range??

I would have thought so yes.

 

[ibizacupra]

Acutally it does misfire with the MAF un-plugged but the rhythm changes. But still no misfires what so ever when actually moving, I'm right in thinking if it was cracked head / piston / valve that it'd also suffer running problems higher up the rev range??

probably less likely to pick up these at higher rpms..

do the leakdown/compression test and take it from there.

 

[ibizacupra]

vacuum lines wrong way round surely?