On 104 HFM /SFI systems , [93 thru 95] AIR code coupled with EGR code and 02 sensor is usually a split/broken vac feed line that crosses the front of the engine
[ under front cover] over to the SOV valves for EGR/AIR . This line feeds both of these , so if it is cracked [which happens all the time b/c they are plastic] , then BOTH those codes will pop and they are both emmisions codes , so they pop the CE.
If you find this to be the case , simply replace that hose with a rubber one.
The 02 sensor also faults b/c the self test for AIR system is ECU monitor of 02 signal for AIR activation. [ looking for lean condition]