I have an 03 Accord ex v6 coupe 6 speed manual. Over 199k miles. Bought May 26, 2021 with 196k miles. Slightly rough idle, CEL. I used a scan tool to check, erase, test, and recheck. Bank 1 Sensor 1 running lean. 7-15 codes say the same things: Random misfire, misfires on all 6 cylinders, and Bank 1 Sensor 1 Lean. The spark plugs were replaced before I bought the car. I tested the coil packs with all good results. I replaced all 4 O2 sensors. What could this be? Clogged cats or bad timing? Do I personally need to replace the spark plugs? I'm frustrated.
Could possibly be an intake leak on bank one or injector concern. If all those check ok I would look into mechanical timing and. Compression on bank 1 to see if there’s any further merit to either of those avenues
