Everytime I start my SHO, it has no CEL. But sometimes after 5 mins, sometimes after 15, the CEL will come on. However after like 5-10 mins it goes out again. I'm not sure if its a sensor or not, but my gas mileage is also not up to par either. I used to have a misfire because the oil in the plug wells destroyed the old wires, but since I replaced them there is no misfire. So I don't think thats the code thats being thrown anymore. Could it be an o2 sensor, or would that be a constant code? I'm gonna go to autozone to get it checked out next week, but I'm just wondering what I could be up against.