Ok, so, after the BG44K incident, new plugs and coils, top tier gas, I thought the problem was over. However, last night on my way home, I started the car and the CEL came back on--- P0303 error again. My gas mileage is great (32mpg @ 60mph). No hesitation, no odd smells. I was thinkin a bad injector, but the fuel is good. Would this fault for an o2 sensor? Any ideas?