the story goes like this - the air pump started turning on/off not just at startup, but at other times (like it does now) and it was sounding funny, louder than normal. It had been very cold here, and I thought that some water that may of acculumated in it froze and messed it up. Then my Check Engine light went on, and it was a air pump related code (can't remember the exact error code). I didn't to anything at the time to fix it, but a few weeks later the Check Engine light went off on its own, and it hasn't come back on yet (its been 2 months now). Just for kicks I replaced the relay, but it didn't make any difference, the air pump still turns on often, and it is louder than normal.