Hey, I do have NX 300 2020 and my engine is running rich. I started diagnosing multiple things using my OBD reader.

One of the first things I noticed is that my MAF sensor is probably under reporting the maximum calculated load I can reach to 70 to 75% while flooring the paddle and I’m not entirely sure if the numbers are good or not so I was wondering whether there is a place where I can see reference number for MAF sensor and other numbers like normal turbo boost pressure, basically more reference numbers that I see in the ECU live data

 

How do you know its running rich?

 

Long term -12
short fluctuates between 2 and -5
fuel smell out my the exhaust
weak acceleration

 

Have you verify " running rich " by pulling spark plugs and examining their appearances. Also continuing to operate vehicle with the RR condition will run risk of damaging cats media.
Apart from pulling numbers with your scanner, IMHO you 'll need to if haven't done so already 1. check air intake system for any partial blockages ( mice nest, clogged filter etc.) 2. fuel injector(s) leakage. Will need to perform leak down tests for determination ( for both low & high pressure fuel delivery system ).

 

I really appreciate your reply I did check all of what you listed except fuel injectors. However I changed my Maf Sensor which I was suspecting and all my fuel trims are back to normal -+4 for Short and long term is around 1

thought it would be helpful to share my experience and I appreciate all of yourhelp

 

Thanks for the update. Glad to know you have found root cause of problem. Happy New Year !