2002 stalls

2002 GS starts runs then stalls turn key nothing...Wait, then it starts.. Sometimes when it does it then you drive it has a hesitation but then it goes away.. Dosent happen all the time.. Couple times a month since it started..

Has it thrown a check engine light when it stalls or runs rough?

Its not actually stalling just like kinda of hard to explain like drops power for a sec or hesitates then it gos back to normal the srs light flashed when it happened... the codes that are showing up are p0421,p0128,po455.. 455 is a leak in the fuel system put a new cap on and it went away but now is back.. 421 is an exhaust leak or o2 sensor... replaced both sensors and stil shows up.. those 2 have been there since i got the car in june the new one is the 128low coolant, thermosat or ect fault...

Have you done regular maintenance lately? Might want to try plugs and wires just to eliminate that if they havent been changed recently. Sounds like you did the o2 sensors recently so those should be ok. Also you should try and fix the fault codes. Its hard to say if there is a direct correlation between a specific code and your issues. What doesnt make sense is why the SRS light flashes.