Xterra Catalytic Converter needs replacing?
Last spring I bought an 02 Xterra SE supercharged. I love this vehicle when it is running properly but have been barely able to drive it since buying it because of a cascade of issues. Most of these have been repaired and it seems to run well but now I have a service engine light that is apparently coding to the catalytic converter and I am tired to putting money into the truck and want people's opinions on what is my best option. Let me go back in the history of the truck because I think it will be important in explaining the current problem. Keep in mind I have limited do-it-yourself knowledge but try whenever I think I can.
I bought the Xterra used with about 120,000 km on it (about 75,000 miles). Shortly after buying it, it started to idle rough and the service engine light came on. The nissan dealership coded it and said that it was a fuel problem and showed us how filthy the fuel filter was. We changed that and were told that if the problem came up again, it would likely be the fuel pump dying because of the clogged fuel filter. Shortly after having the service engine light cleared, it came back on and we suspected the fuel pump, which in fact seems to be ok. Instead of that, it coded as a single cylinder misfire. We tried flushing the fuel rail and that seemed to help for a few 100 km but the problem came back so after some investigation, we had the #4 injector rebuilt. Turns out that the injector was seeping fuel and flooding the #4 cylinder, and all of this makes sense to me. About 1000 km after that the service engine light came back on. This time it coded as the catalytic converter (I don't have the exact code unfortunately). The dealership said it was maybe just some bad gas or a residual from the previous problem and that we could try clearing the light and see if it came back. Right after that, I moved about 600 km and a few days after arriving, the light came back on. I assume that this is the catalytic converter again, but don't have a good shop that I trust yet and haven't taken it in to get checked. Keep in mind, the whole time that this light has been on, the Xterra has not been idling rough or anything like it was before when it was misfiring. The only thing it does, is suck down gas, but I think this is pretty much expected for the supercharged model.
From what I have read on these forums, everything makes sense and a cylinder misfire could cause the catalytic converter to fail. What I do not know is if the catalytic converter will continue to get worse until it gets completely plugged, even if I have solved the underlying cause and my question is, what should I do now? I see a few options.
1. I could keep running it with the service engine light on, hoping that the cat is just running below efficiency.
2. I live in Alberta where there is no emissions testing, so I could just remove both catalytic converters and put in a straight pipe.
3. Try to find a good muffler shop to put in an after-market cat so that I don't have to pay the high prices of the dealership.
4. Suck it up and go with genuine nissan parts and hope that putting the extra money in will fix everything once and for all.
As far as I understand from previous research, options 1-3 will not clear the service engine light, but I think I can live with that if I'm not going to do more damage in the long run.