[internic]

I wanted to bypass my EGR to get more horsepower, but didnt have materials to plug hoses, so i unplugged the valve from its harness. I took it for a test drive, and it seemed to have more power but it sounded like it was running too rich. I got back home and noticed the service engine light was on, which didnt surprise me, thats what i get for unplugging crap. So, I plug the valve back in, start it, and the light is still on. But then i leave the truck alone for about 12 hours and i get back in it to go home, and the service engine light is now OFF? why would it be on and then off? is there still a fault code in the ECU? or was it just the computer re-adjusting to having the valve hooked up again? im really freakin confused, i would love it if someone could explain it.

-Nick