1.4 TSI misfire

Hey all,

Figured I'd start a new topic rather than continuing the rattle thread as the rattle is now well and truly gone. What's emerged after having a new chain and all the gubbins including vvt pulley is a very irritating misfire which only occurs at idle. The engine used to idle solidly at an audible and bottomshake reading of zero. The car now records multiple misfires in cylinder 4, and only very occasionally will it record them in other cylinders. The engine is a 122 CAXA lump, has fresh oil and filter, fresh air filter, new spark plugs and even a new coil in a bid to see if the fault moved with coil packs. It however, does not. Having visited a friend yesterday who has VCDS, the faults increment on cylinder four - sometimes really quickly and other times one recorded every 5/6 seconds. Looking at the fuel trims, it had recorded 

Block 32

Adaptation idle  -0.8%

Adaptation Partial -9.4%

Block 33

Lambda Control  sensor 1 1.2%

Sensor voltage 1.46v

I will check these figures again in a moment to see if the values have changed since she's driven to work a few times but I do know that the idle missing and juddering is still there. Are there any common vacuum hoses that break on these engines at all? The way it behaves reminds me of how one of my uncles old Fords would judder due to vacuum leaks which were hard to locate at the time. Having just started the car and running it up to temperature, misfires were recorded on multiple cylinders during this phase. Once up to temperature they were only recorded on cylinder 4. Four has the new coil pack fitted and has had a new plug fitted also. I'm leaning towards this being some sort of vacuum issue but could be barking up the wrong tree here? Having removed the oil filler cap whilst running, the engines... running wasn't affected by this removal. I've felt for vacuum at the end of the breather on the camchain cover and you can feel weak vacuum coming from that breather hose.

Really appreciate any help, I struggle to see that the garage would have touched anything else but I assume some hoses would have been disconnected, and potentially moved for easy access to the plugs when it had new plugs.

Thank you.