wierd problem P0135 and P0446

[jpdoane]

I have a wierd problem with my 99 V6 camry

My cel came on a while ago, had it checked, p0135 - O2 sensor

REplaced it and the light stayed on. Eventually discovered I replaced the wrong one (V6 has 2 upstream o2 sensors - oops!). REplaced the correct one (behind the engine by firewall), and light went off (without disconnecting battery, or clearing - turned off while driving). Yea!!

Couple days later, cel came on again. Took it in and there is the same P0135 (o2 sensor) along with a new code, P0446 - Evap Emmission control, System vent control circuit malfunction.

MY questions are these:
-how is it possible that my cel went off by itself and then came on again with the same code? What could be up with the o2 sensor? How do I troubleshoot? I really don't want to buy a third o2 sensor!!

-is it possible this issue has anything to do with the P0446 code? could a bad o2 sensor cause issues with this system?

[Cyorke]

pull the EFI fuse and leave it out for a minute. then drife the car and see if the light turns on again. You are going to need a repair manual for your car taht lists out what to inspect with the P0446 code you ahve gotten. The O2 sensor is probably because it wasnt cleared correctly in teh first place.