Hello, Just took my truck to Advance Auto to have them check why my check engine light was on. 2004 Chevrolet Silverado 5.3 It came up with code 0135, which is an [02 sensor bank 1 sensor 1]. I haven't noticed any erratic idling or loss of fuel mileage, or any difference in the way the engine performs. I'm wondering if I can simply swap the 01 sensor for the 02 sensor. From what I have read, it appears that a faulty 01 sensor can affect fuel economy, but I've yet to find anything that describes the symptoms of a faulty 02 sensor. I understand that the 02 sensor monitors the catalytic converter and 01 monitors oxygen. I would think that by swapping the two it would at least tell me if sensor 1 is actually faulty, since I could get the truck checked again and then it should show that 02 is now defective. If it continued to tell me sensor 1 is faulty then I would know that something else is up. Does that make sense? And since the 02 sensor is not giving any codes for a bad catalytic converter then it is obvious that it is fine (at least at this point). Yes, I'm cheap and don't want to buy a sensor, but more importantly, I don't want to buy one and have the machine give me the same code. I also would like someone to confirm for me that the bank 1 sensor 1 is actually on the drivers side ahead of the catalytic converter. Thank you!