o2 sensor not throwing codes?

is it possible for a bad o2 sensor to not make the CEL light come on? i have replaced one sensor already, and the problems got better, but didnt go completely away. when the CEL was on, the guy running the codes said one of the sensors was getting no signal, and the other one was reading wrong, so i replaced the no signal one, and the stalling has gone away, but i still have jumping idle, hesitation at lower RPM's and not driving with "full power"...it feels like theres only 2 cylinders working instead of 4, and then it will "kick in" and lunge forward and take off with full power. the problem seems worse at operating temp, at cold start it seems to be fine. any ideas? could it be the o2 sensor? or could it be plugs/wires? im cleaning the EGR valve later hoping it will help with something, but at this rate i guess it couldnt hurt

any helps or tips will be very helpful

o2 sensor issues

Hello i was reading your posting about your protege issues, and i have a similar issues when it comes loss of power... a Neon kick my ass today.. lol..
i was thinking my o2 senors are bad but i have no CEL light. i was woundering if you fixed your problem