Curious if you have solved the P0053 problem? I am going through a similar issue with my 09 Aveo5. I had a drivability problem creep in the other day on a 20 mile drive...hesitation and rough idle. No CEL, but when I got home my scanner showed P0053 pending. Seemed logical the O2 sensor might be bad at ~160K miles, so changed it out and cleared the code. Three or 4 starts later, CEL is on and showing only P0053. Interesting that driveability seems ok at this time. I saw your forum note and wondered if I might have a similar problem.

John B