Diagnostic trouble codes P0171, P0172 and P0420

I have replaced the mass air flow sensor and the new code that came up was the P0172 along with the other repetitive two mentioned above. I've replaced spark plugs not too long ago. Also, a smoke test for vacuum leaks to report none found. As well as a pretty extensive physical inspection for looking and listening for further possible vacuum leaks with none found. Unless something could have been overlooked or not seen. I've gathered as much information from my scan tool with live data including the graph data. I'm not as knowledgeable when it comes to the correct numeric values that I should and shouldn't be getting. I've gotten a handful of info from those helpful individuals on YouTube; however, I just haven't received much pointing me in the right direction so far. I can report my symptoms as intermittent hesitation when driving such as loss of acceleration completely when pressing on the gas pedal. Now this seems to occur very randomly without other symptoms associated. It may stall but not always. I've simply restarted my vehicle at this point, and it goes back to normal(strange). As though it resets or something. So, it's been a bit difficult to diagnose this thing. Also, I wanted to mention that when I'm in park while idling. It starts to idle up and down(not very pronounced), but enough to show that it's about to stall which it eventually does and the engine dies. This occurs after about ten to fifteen minutes of idling in park. Never any backfires, no misfiring, and not much other strange activity except maybe a strong exhaust smell for the most part but no smoke from tailpipe. If you could direct me to some better info into this situation, I'd greatly appreciate it. I could provide my scan tool data if need be and/or if I could be provided with what would be normal/average values that I should be seeing according to my vehicle or a more generalized idea of correct values that shows me any accurate or inaccurate readings according to these diagnostic trouble codes. It's been one hectic situation and a real headache, and any information on this matter would be very helpful. I'm hoping that I covered most of my vehicle's symptoms, but I will make mention of it if it crosses my memory soon enough. It's been really hard to figure this thing out so your help would be of great assistance! Thanks!
-Mark

PS. My car is a ZX4.