Miss fire at idle ed30 gti

[e4n94]

I have a 2008 golf gti 30 edition I have recently noticed the car Miss firing on idle and only on idle I have put the engine under load but runs ok no problem. I change the spark plugs 2 months ago and recently change one coil pack due to a code p0302 cylinder 2 miss fire but still the car Miss fires on idle.

The other code I have is Random cylinder missfire p0300. I was thinking it could be a injector so I tried some red X but still no joy. Am I right in saying it could be down to carbon build up in the inlet and if so how much of a job is it to remove the inlet manifold

Thanks

[pudding]

Injector.  Probably number 3.  It's only noticeable at idle because of it's the lowest rail pressure.  Give it some throttle and the pressure increases and overcomes any blockages/mechanical pintle wear.