This is just a little info on some codes Iv'e incountered, and fixed. P1131, P0420. A few months ago I started getting a cel every morning then shutting off as the engine warmed up, then it stayed on for a day or two. Had the code read and it was the P1131 upstream bank 1 lean, O2 sensor went bad. So I said heck I could live with this for a while, well soon after the cel stayed on permenantly, I had it check and it read P0420 cat below threshold. Now I said oh s**t, I just screwed up the cats. Anyway I change the O2 sensor and cleared the codes and all is well, as a matter of fact It perfoms alot better and better gas milage. So if you do get any of these codes just beware if you dont change that O2 sensor you may damage your cats, just a word of advise from a flatliner!!!!! By the way Im running on 107,000 miles, every day driver of 100 miles plus a day, and it still runs like new.
