Toyota Repair: Highlander 2001, p0440, p0420

Question
About three years ago I accidentally put Diesel fuel in my 2001 Highlander. I had it purged and have ever since had the P0430 and P0420 codes which I ignore because the car has run fine.

Lately I've had trouble accelerating on the highway and I'm now getting the P0361, P0440 and P0446 codes.

What should I do? I'd rather fix it myself if I can. I have amateur to advanced auto skills (stress on the amateur).

Answer
The p0440 and 446 are evap system codes, there is a leak in the evap recovery system, this could be simple as a leaking gas cap to something more complicated. Try replacing the gas cap and clear the code by disconnecting the negative battery terminal for about ten seconds.