Three days after buying my Cobra I got a check engine light and it turned out to be a bad O2 sensor. The dealer changed the sensor under warranty. Fast forward 1.5 months and about 75 miles, and the check engine light comes on again. I go to Advance Auto to check the code (warranty over) and they tell me it is #1 O2 sensor, bank #1 slow. The guy resets the computer and suggests fuel system cleaner and says that if that if that doesn't remedy the problem then I'll need an O2 sensor. Fast forward 1.5 months and about 120 more miles and I get the light again. Same code. I'm thinking this is not an O2 sensor problem because it's already been changed. Anybody ever have a similar problem? Should I dump $69 into a replacement O2 sensor?