AQY Engine Misfire

[Golfcatch]

Got a 2.0L MK4 GTI, where it has rough idle (can feel it in the seat!). Initially the rough idle was only noticeable after the engine was warmed but now it is noticeable after minute from a cold start as well while idling.

Items change (over a period of 1 year)

Spark plugs (NGK)
Coil Pack (OEM)
HT Leads (from eurocarparts)
Alternator (voltage was around 13.5 max before) (Remi)
Rocker cover gasket (oil leak, looks like oil was leaking on to the exhaust manifold also it was brining the smell into the cabin - intermittent) (elring)
Radiator (due to looking coolant) (not sure!)
MAF (AMM - Bosch)

For about six months didn't have the misfire issue, after adding some engine stop leak and the radiator change, but for the last six months it's been there.

Had VCDS with for a couple of days, so was driving around with it hooked up.

Codes - P03000 (intermittent) and P0303 (intermittent)

The engine management light is currently on and sometimes it goes off but only to re appear when I've been idling in traffic.

In the morning if I reset the EML, it drives OK till I have to idle in traffic and slowly you can feel the misfiring the seat and if it carried on for more than 30 secs the EML comes on. On a normal OBD II scanner it just comes up with the code P0303.

Once I was driving around for 20 mins with VCDS, I believe measuring blocks 15 and 16 where it shows the misfire for each cylinder, when idling @ less than 800 RPM you can see the misfire in numbers in Cylinder 3 go up and as the speed picks up the misfires go to 0.

Another thing I noticed there were misfires in Cylinders 1 and 4 as well in addition to 3 (see attached).


I’ve also attached another one which shows O2 sensor values along with Engine Load, etc.


Any pointers on what should I do next would be greatly appreciated.


Thanks
GC