There have been some extra hot days recently. My 12 Sonic (1.4L manual with just under 150K miles in the Northeast) had coded twice with P0420. The first time @ over 110F and the second time today when peaked at ~95F. The car was driven in between the two events without an alert (after a reset when it happened the first time).
It's sounds like it's likely going to be either the cat, or one of both of the O2 sensors. Because the sensors are relatively cheap to replace, do you think it's a good idea to try that first? Would a $30-40 pair of sensor be good enough.
It's sounds like it's likely going to be either the cat, or one of both of the O2 sensors. Because the sensors are relatively cheap to replace, do you think it's a good idea to try that first? Would a $30-40 pair of sensor be good enough.