2.5 Lean Conditions
I have error codes 21 (O2 Sensor Circuit) and 51 (Lean Conditions Detected). I did have 14 too (MAP Sensor), but a new MAP sensor made that code go away. SO doing some research on lean condition I saw people saying things like you could do some serious damge like burning holes in pistons and things. I am assuming I have to replace my downstream O2 sensor and all will be fine. I have driven it probably 200 miles, and about 3 hours on the trails since this started. I know some people lean on their carbs on purpose. I am just curious if I might have done any damage, or how serious of a problem this could be. I am also kinda surprised because I cahanged my O2 sensor about a year ago. When it went bad last time I did not get error code 51, only 21. Any help with this would be great before I go spending more money.
Complete rebuild axle/engine/everything swap in progress:
Parts already gathered for assembly: 2001 Ford 302, 1990 Mustang GT 5.0 ECU and wiring, NP435, NP205, Pair of axles from 04' F350 SuperDuty (Sterling 10.5 Posi rear, Dana 60HP Front-Both Disk Brakes 3.73 Gears), 37" H1 Tires, 9" lift TJ Coils for 2 link conversion in front, Stage 2 Clutch Kit, 3 Row Aluminum Radiator, Chevy Astro Steering box (4" front Stretch), XJ Rear Leaf Springs (6" Rear Stretch), and lots more.