Rep Power: 0

Started to experience hesitation, stalling, and sputtering when accelerating from standstill. Need to put in N when sitting at a red light, gets really bad when I turn on the A/C. Trying to troubleshoot by process of elimination. So far I have changed spark plugs, spark plug wires, distributor cap, air filter, and fuel filter. The next thing on my list is the O2 sensor which is fairly easy to reach on this model, but not sure if there is anything else I should check/replace first. Any input or suggestions would be greatly appreciated!

 
Rep Power: 174

Tried cleaning your Idle Air Control Valve (IACV)? http://honda-tech.com/showthread.php?t=1575913
How are the fuel injectors? Do you use top-tier gas only? Do you ever use any additives to clean the system?