Using an OBD reader while driving, my long term fuel trim is consistently 3% higher in Bank0 compared to Bank1. It doesn't matter if I'm idling or on the highway. The absolute values are usually near +3% in Bank0 and 0% in Bank1.

Normal variation or bad?

This is a 997.2 S.

 

Using an obd reader while driving is bad

 

Plus or minus 10% is the acceptable range for fuel trims. Brand new cars should be plus/minus 5%. So you are w/i the acceptable range. For an accurate value you should add short and long term together, as they effect each other, and see if they fall w/i those ranges. Positive fuel trim means you are running lean (adding fuel ) and negative is rich (subtracting fuel).

 

I would expect some difference between the banks I doubt both oxygen sensors would age exactly the same.

 

Okay, so not a big deal then. Thanks for the responses!