Hey, I've got 99k miles and I replaced my after-cat (bank 1, sensor 2) O2 sensor in September. Starting in about January, my check engine light comes on for the same sensor (code 043 - but only when it's raining outside. It's a universal sensor, yes, but I'm 100% confident in my wiring. I also have an AE86 that I did the engine swap (to blacktop 4age) on and wired completely myself.

I didn't use that stupid 'universal sensor' brick that it comes with, I soldered the wires together and used heat shrink tubing. The clips are fine, no corrosion, the sensor is tight, it all seems ok.

One thing that made it NOT come on for 2-3 weeks (even in the rain), I cleaned my MAF with carb cleaner and qtips. (it also significantly raised my gas mileage after this from 29 to about 35).

Short of just replacing the sensor again does anyone have any ideas?

Thanks