2010 1.4L GTI 6R - MISSING Cyl 1 & 3 on load

[jebusv20]

Hi there,

I'm having an issue with my Polo missing under transient load that's starting to really annoy me. The Miss is in Cylinders 1 & 3 and has been getting progressively worse for since October. In November during my normal service I put in new spark plugs and ran through upper engine cleaner, and the car ran fine until late January when the miss returned.

I have since swapped the coil packs 1 to 4, and 2 to 3 and the miss continued on cylinders 1 and 3, additionally I used more upper engine cleaner, and the engine feels better but close to perfect (potentially no change, could be in my head). Using logging tools on my phone over OBD2 I can confirm there is no movement of AFR or dips in Fuel Rail pressure during the events.

More about the miss, it only occurs during transient loads, if I'm high in the rev range and smashing it on a track, the drag strip the car is fine. It's only low rev and high loads that the issue occurs.

Any ideas of where to look next would be great as I'm scratching my head here.

[Snail Style]

Comp and leakdown test

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