Your thoughts on this scan

[kenimpzoom2]

94 Firebird LT1 - keep having some issues with hesitation. Take a look at this pic of a scan. It hesitated around 500-520 seconds Would you say my left O2 Sensor is bad?

[NomakeWan]

Either that or one bank of your engine is having serious mechanical issues. O2 sensors are cheap and easy to replace, throw one in there and see what happens I says.