Engin making ticking sound. and bogging out while idleing

[Mikky350z]

When I have my car turned on, every once in a while it sounds like the engin loses its normal idle... I watch the rpm on the gauge and the needle drops then gose back to its normal state.

I understand that one or more then one of my O2 sensors are bad I had a OBD check but the retard at the oil place I went too reset my servis engin light and forgot to tell me what bank it was. Could my engine be bogging out due to more fuel then air being fed into the engine itself.

Or would it be a piston missfire?The ticking is not a knocking sound its a tick tick tick tick. Im thinking maybe the timing chain? But im reallly not sure could be injectors could be lifters?

Could all boil down to the O2 sensors.

Anyone help?