Connect the o2 sensor up to a multimeter or oscilloscope. then unplug any vacuum line, thus instroducing unmetered air into the engine (lean condition). and watch for sensor output change.
Also the o2 sensor should cross the 0.45v point about twice per second if working well.
If the car is idling rough then it;s not teh o2 sensor as it's input is not taken into consideration in open loop.
Also don't touch the MAF sensor with anything just spray it with cary cleaner, the wire type are very fragile.