Had a few questions regarding a new to me Mazdaspeed 6 (got it at 160k miles, now at 177k). First issue I had was a EGR P0401 code which lead me to taking out and cleaning the EGR valve as thoroughly as I possibly could with a degreaser. Put everything back in, started the car up and it was essentially bucking in the lower gears, almost as if the car wasn't getting enough oxygen to get the RPMs up.

That led me to bring it to my mechanic who ended up replacing the mass air flow sensor in early July. While doing the work on that, the power steering pump started to make noise (which is annoying, but I'm not sure if it's related to any issues or if something is just loose) and now the car sometimes stalls at low RPMs which never used to happen before. But the bucking that I experienced was resolved after the new air sensor was installed.

On a small side note, it burns through oil like crazy and even when I change the oil completely along with the filter, the oil immediately turns jet black.

Now the car needs to pass inspection soon and according to my AUTOPHIX it has passed the MIS, FUEL, CCM, and HTR but the CAT, EVAP, O2S, EGR haven't passed yet (I have tried to follow this ( https://corksport-com.cdn.ampproject.org/v/s/corksport.com/blog/how-to-clean-your-egr-system/amp/?amp_js_v=a3&amp_gsa=1&usqp=mq331AQFKAGwASA=#aoh=15918236122285&referrer=https://www.google.com&amp_tf=From %1$s&ampshare=https://corksport.com/blog/how-to-clean-your-egr-system/ ) websites guide to flipping the sensors but I can't do the guide in the order it is listed in where I live at easily). It is also showing the AWD and brake light on the dash and throwing up a P0328 code currently (Knock/ Combustion vibration sensor 1 Circuit high bank 1 or single sensor).

So the question is what do I need to do to get this thing to pass inspection and is the P0328 code going to hamper it? Do I need to resolve the check engine light before the sensors will flip? Do I need to throw the car up on a lift and go through the website I posted step by step instructions to flip the sensors? Why is the oil so dark? Or do I just have to bring this into Mazda and let them work on it?

Thanks for any help, it's really appreciated. And for the record I absolutely love the car and the way it handles and will end up getting another one when this one eventually dies (which hopefully won't be for a long time).