I have a 2003 Civic LX (Sedan) with a manual transmission.

I was driving it and pushed the car a little too hard (I guess) to pass another vehicle up and suddenly lost power, CEL came on, and I had to pull over to the side of the road. Towed the car home as it would either die on me under load (trying to drive in gear) or not idle (sputters around 500 RPMs and then dies; normal idle is closer to 800 RPM warm). The car will rev up, but will die or have no power when I try to drive it.

I checked the engine codes and got P1456 and P1457. As far as I understand it these codes shouldn't be causing the problems I'm having with the vehicle. I also did the basic job of checking the fuel cap and didn't see any problems there. There's no smell of fuel in the car, so I'm a bit stuck at this point what to do next, short of having a garage look at it which I would prefer to leave as a last resort.