2019 Nissan Altima - Help with O2 sensor

coded mass air flo problems so i replaced the maf sensor and bank 1 o2sensor. Has no power at all like 10mph. Going to check for vacuume leaks next anyone have any ideas.Runs in limp mode i guess. I took the o2sensor out completly gained speed but when replaced it ran bad again. When i took out the o2sensor i sprayed in seafoam to help clean the cat,

Welcome to the forum…

Is this the 2.0L turbo or 2.5L non turbo??

What are the codes??

Try unplugging the MAF sensor to see if it has anymore power…be careful it might stall easily at idle…

I have seen a lot of (older) Nissans have to have the ECM’s flashed to recognize the new parts…

Did it have plenty of power/speed right before you replaced the MAF and o2’s?? And now after replacing them, no power??

If there are any stored diagnostic codes, address those. Beyond that, performance improvements after removing the O2 sensor (I presume you simply unplugged it, if not explain what you did) suggests the computer isn’t able to achieve the correct a/f ratio in closed loop operation for some reason. Fuel trim tests and observing the o2 sensor’s output signal is where your shop will probably start looking.

Exhaust restriction? There is a recall for the secondary catalytic convertor.

NISSAN RECALL CAMPAIGN BULLETIN (nhtsa.gov)