How many o2 sensor a 2010 Acura MDX have ?

You will have an oxygen sensor before and after each catalytic converter. So, you'll have a total of 4. EGR and Oxygen sensors are completely different areas. Sounds like you need some hands on assistance. Your symptoms don't add up to your question; you'll be wasting money and resources guessing instead of just getting professional assistance. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops