Check Engine came on, so I used my Durametric to find out what's going on, and I got the following pair of fault codes:

P2177 Mixture adaptation checksum error bank 1
P2096 A/F ratio correct beh. cat c. bank 1 above lean control limit

Does anyone know what this means, and how I can correct it?
My guess is I have a faulty O2 sensor in bank 1. I believe bank 1 is the side with cylinder 1, but I don't know which side that is, or which sensor (before or after the catalytic converter) is bad. I believe there are no air leaks, the gas cap is good, and I just cleaned the MAF. Could be plugs or wires by my guess is an O2 sensor. If so, which one?
Help!
CATTMAN

 

Driver's side is Bank 1 (in the US). I would agree with your diagnosis of a faulty O2 sensor, but it could also be a vacuum leak or your cats are going bad.

To diagnose the O2 sensors, the simplest thing to do is to swap one of them from bank 1 to bank 2 and see if the error follows tgat sensor to the other bank. If not, repeat with the other one. If neither of those moves the error to Bank 2,its not a bad O2 sensor and you need to keep digging. Best diagnosis method to look for a vacuum leak is to smoke test the intake or in the absence of findi g a shop to do that, sprat a little ether around in various areas and listen for the RPMs to increase.

If you have borderline catalytic converter function, an O2 spacer like people run on 100 and 200 cell high-flow cats might decrease the sensor sensitivity enough to keep the CEL from coming back.

Good luck and post up what you find.

 

Thanks, I'll try swapping around the O2 sensors tonight. Should I reset the fault codes in between?
Here's the issue:
If I clear the fault codes, that will eliminate the CE light. But I still won't pass emissions because there will not be enough data recorded to pass. It won't be a fail, but it won't be a pass either. It will mean I have to drive a couple hundred miles in different conditions, etc. before enough data is generated to pass. But, during those miles, the CE could re-appear. I don't want to have to drive hundreds of miles between each swap of O2 sensors to find the culprit. The threshold to cause the CE light is the same threshold to get a pass- it's data/ miles based. See what I mean?

I guess the simple way of asking this is: will a faulty O2 sensor throw a code immediately, or will it require hundreds of miles of "data" before it does?
CATTMAN

 

Yes, definitely reset the fault codes before restarting the car with the 02 sensors in their new positions. If it takes hundreds of miles for the CEL to return, those are free miles