Hey all,
Last month my CEL came on. I checked it out and it was a P1647. Bank 2 upstream O2 sensor. I replaced it and CEL went off for a while but came back on. This time it was the Bank 2 downstream. I replaced it. I also found that my air intake tube was broken at the ribs, my intake manifold was leaking, and there was vacuum line under the intake that was broke. I fixed all that. The car runs better than it has in years, but now my CEL is back on and it is the Bank 2 upstream O2 sensor again. Car still runs great, but I hate driving it around with a CEL on. Any ideas what could be causing this?

What make sensor did you buy?

I am thinking that is the problem as I bought some cheapo from Ebay. Probably made in the far east somewhere. It was not a name brand that is for sure.

Try cleaning the MAF sensor, as well. Also check the new O2 sensor for broken wires. Barring that, get a good Denso sensor, instead.


It would s also be useful to know know what long term fuel trims you are seeing on your OBD reader: you may still have a vacuum leak on the left side . . .