CirrusWRX, thanks for posting this. I've had this problem intermittently for about a year. I've cleaned the maf and replaced my ScoobySport catback with OEM. At one point it actually went away (CEL went off while driving), but now it's back. I'll reset the code and it'll return a few days to week I'll go through the steps above and report back. What's interesting is that it seemed to happen after Subaru put in a new fuel line (for the infamous gas smell problem). I'll be looking at the FPR item first.