well it's been like this for 20k miles now. I hope it's not the same case as urs ^

I've been told from it's running rich to cleaning the fuel system, whatever that means.

 

So you blew your hg from running rich? I would have thought youd wash out your cylinders interesting. Maybe you had more problems with your tune then just running rich.

 

my car used to blow a bit of black smoke up near redline too. no big deal. thats just the ecu richening itself out to stay safe up by redline.

i dont think a failed ac pump will cause a massively rich situation. maybe your o2 sensor is on its way out. if a sensor gets clogged or is dying it will lkely read leaner, and the car will over compensate in terms of fuel.

throw it on a dyno and check the AFR's - if you see numbers in the low 10's you'll know your problem!

 

Either way I would get your ac fixed asap.

 

Plugs not firing 100% at high revs?

 

I'd recommend to take your car to back to church auto and have the Tuner check it.
GL.