My 2K V70XC has been up and down lately. It will run like normal and then bog down for a while, and then check engine light comes on. The codes are P0014 exhaust camshaft position timing over advance and P0422 main catalyst efficiency below threshold. And then it will quit bogging and run fine again. And then it will run like crap again. There seems to be no pattern to when it does it. If the timing belt was off by a tooth it would stay running crappy all the time, right? I'm really hoping it's the sensor......any help would be much appreciated.