[Teddylongtooth]

My slight rough idle is back and the harmonic vibration during long hard excelebration is also back and maybe never left. I did some research on the n63 engine and it appears that 2 cylinders on the same bank fire consecutively which some say is the cause for the slight rough idle.

This is the firing order 1-5-4-8-6-3-7-2

This is the how the cylinders are laid out (nevermind the m5 manifolds) the cylinder numbers are the same. If you follow the firing order cylinders 8 & 6 fire consecutive and then 2&1 at the end of the firing cycle which are on the same side of the engine. Most engines criss cross back and forth and don't fire 2 cylinders on the same side consecutively. This is probably what I'm feeling as a slight rough idle, the car runs good and has lots of power so I don't believe anything is wrong. This is probably how the engine is supposed to feel, I'm not saying any of your rough idle problems are the same as mine, you may have a real problem, I never had any check engine lights or what would be called a miss fire or a lack of power. If you replaced all your plugs, ignition coils, fuel pumps and you still have a slight rough idle with no check engine lights this is most likely what your experiencing.

Firing order 1-5-4-8-6-3-7-2