Did anybody had a problem like mine?
Last Sunday, I filled up gas at cheap local gas station. After about 30 mins, the "check emission system" light came on. I re-tightened gas cap again but, it's not going away. I got the code scanned at Autozone, it is P0135 / Oxygen Sensor Heater Bank 1 Sensor 1. Is it upper steam sensor? Would bad gas cause the CEL?

 

Two times my 06 6MT tsx showed the tighten gas cap-Even after tightening the cap the check emission message would appear. I had the dealer check it out-they found nothing wrong and reset it-no further problems. Oh the messages showed up after I had the car's annual state inspection and getting gas in NJ where you can not pump it yourself. Both times the cap was loose

 

Yes. Air / Fuel Ratio Sensor. Sensor is located before the Cat. They run about $226 from an Acura online dealer for the replacement. How many miles do you have?