Hey, I have a 00 LS1 that is showing cyl missfire in #7 and #1. Scan showed fuel system to lean on bank 1 and 2. I have 02 sims and replaced them. It was fine for almost a day and now it's doing it again. The ses light came on and is flashing at me. I didn't get to scan it yet, but I'm almost positive it's the same thing since it's doing what it did before. Any ideas or suggestions?

 

front o2 sensors?

the o2 sims have nothing to do with the A/F ratio...so there was no point to replace them unless a code came up for a rear o2 problem.

NOW...you didn't put sims on the front sensors did you?? cause those are NEEDED by the computer to adjust a/f