I too have been having a problem with a code 13 on a buddies integra, though my scenario is a little different. We just put a turbo kit on it last weekend. We finally got it tuned to the point that we can drive it. (pretty sad...don't buy an ebay kit unless you know what you are doing) So it seems that we are only getting a code when we end up giving the motor boost. The odd part is that it is intermittent for when the light actually comes on. I was hoping that it was going to be as simple as putting a different map sensor on it, but it doesn't seem like it will be that easy if the BARO sensor is in the ecm. We were planning on trying to put a GM 3bar map sensor in, though yet again, im not too sure if this will solve our problem.

On another note, the whole incident with your emissions test....The car runs fine untill that light comes on...and then the car just dumps fuel. Even just drivnig it nice down the highway. It goes all the way up to 10.0 on the air/fuel (rich) and it won't try to compensate when we give it gas. It goes into like a default, where it won't give it any more fuel when we give it more throttle, which then makes it go all the way lean at like 17.4. So that would be your emissions problem, especially for cali.