Hi, I have a check engine light on causing my suv to have jumpy throttle and stalling issues when the gear is in drive. I have a Ford Expedition XLT 4WD 2004 4.6L engine. I have gone to Auto Zone where they checked the codes and told me that it was an error associated with an O2 sensor. Was not sure, so I went online to investigate it. Found these things:

1. Clean the MAF(Mass Air Filter) with electronic cleaner. (Heavily Spray the MAF).
2. Wait to dry and do it again....... Install MAF
3. Issues with fuel injectors (being dirty).
4. DPFE issue being faulty........ Or a EGR faulty.........

I'm not a mechanic by all means but can change brakes and small jobs like that. Just wondering if anyone can give me some advice as to where I should start. Step one seems like the idea but I have already tried that. Did not work. Fuel injectors too, not work. Need some advice. Thanks so much for taking the time to read this.