I have a 219k '01 xtracab 2.7l. I've been getting a CEL with a p0136 code (oxygen sensor malfunction, bank 1 sensor 2) for the last 2 weeks. I have reset the codes/ecu 3-4 times and the codes keep coming back. The only consistency regarding when the CEL comes on is when I have about 3 gallons of gas left. At first I thought the light was only coming on when doing 67mph+/2200rpm, but it just came on while doing about 30mph.
I went to my buddy's house and he got a live reading of exhaust/emissions flow with his scan tool and we noticed something that didn't look right- the reading for the upstream o2 sensor was hovering around 3.2xx but the reading for the downstream 02 sensor just said "0" and didn't change, which seemed suspicious. I have a URD o2 "simulator" (which is basically a conditioner, working in conjunction with the downstream o2 sensor) with one cat and until now, my truck has been running absolutely amazingly since I installed it 3 months ago.
Ok that's all the info that I can think of. My question is this-- can somebody please get a live reading from their 01-04 Taco and tell me what that number for a functioning downstream o2 sensor is supposed to be? I don't wanna waste my time and money replacing an oxygen sensor that still works (yeah yeah, I know, it's a freaking high mileage sensor and definitely most likely the problem, but money is tight and I wanna know everything I can before going out in the freezing cold to work on my truck)