I got a 97 camry V6 and I just replaced both upstream oxygen sensor, the car runs so much smoother now. But the problem is the same check engine light came back on after a couple miles of driving. Any ideas why is this happening?

trouble codes is P0130 bank 1 sensor
P0133
P0150 bank 2 sensor
P0153

http://www.obd-codes.com/p0130
http://www.obd-codes.com/p0133
P0150 and 153 same except bank 2 sensor

Double check connections and concider using OEM sensors if you didn't. Any exhaust leaks?

It may be that your Engine Coolant Temperature sensor is malfunctioning and you are never going into closed-loop metering. Check the ECT sensor.

Nope no leak