2006 Pathfinder P0011

[forcryingoutloud]

I'm hoping someone here can give me some advice...

I've had the SES light on with a P0011 code (and sometimes P0300) for a while now. There have been no noticeable performance issues, but my MPG has definitely been getting worse lately. Unfortunately I can't pass AirCare with these codes present and I'm only able to get 3 months insurance until I can fix it. The codes always return after about 10 - 20 mins of driving once I clear them.

These are the things I've tried:

1. Engine flush and oil change
2. New spark plugs (this was more to address the poor MPG)
3. New camshaft position sensor.
4. Battery disconnect to reset the ECU

Any suggestions? Should I try a different type of oil? (I'm due for a change)

Thanks!