I had the check engine light go on today and the car seemed to idle rougher than usual. I drove about 15 miles and checked the obd and got a 2-1-2 code. I reset the obd and the check engine light went off. I started the car and noticed the idle was smoother and drove another 10 miles and everything is ok. 2-1-2 indicates a problem with the O2 sensor. Can it fail intermittantly? Is this an early sign it is failing? What should I do?
Also, I noticed the o2 sensor is connected by two white wires and a black one. If I install a new one, are the white wires interchangeable? Can I use crimp style barrel connectors, or is there a better way? And, the FAQ talked about a o2 sensor wire junction by the oil dipstick that should be checked. I don't see it. Should the 240 have this? Thank you.