Strange thing happened one day on the way to my American Legion. All of a sudden my engine idled rough and would have died at a stop if I did not shift to neutral and rev to keep running. I was a block away from the Legion and pulled in with it running bad and shut off. Had a few drinks to build up courage for the dreaded drive home and when started it ran like a top. The CEL was on and showed a problem at sensor 1 bank 1. I replaced all 4 sensors and never had a problem again. When I did have the initial problem, the CEL was on then.