so last night i replaced the upstream o2 sensor (alone with the whole Y-pipe) after 2 days of driving with the stock one broken off. so no surprise that the CEL came on. well today after 80 miles of driving with the light on i decided to pull out the scanner and clear the codes. of course there was the 2 codes for the sensor but the third was a surprise, p0301 (cylinder 1 misfire).
before the trouble with the o2 sensor i didn't have any codes stored, so my question is this.. could the sensor (or lack of) have caused the misfire? i've driven roughly 6 miles since clearing the codes and the light hasn't returned.