2003 Silverado 1500 4X4 5.3L 93000 miles I started my truck today after it had been sitting for five hours while i was in school. and it was a little hard to start, then when it did start, the service engine light came on and the cluster read "Reduced Engine Power". it idled at about 1000 rpm. had no throttle control at all. i shut it off, let it sit for about 5 minutes, started it back up and the service engine light was still on but i had throttle control now. does anyone know what would cause this? and is an easy fix that i could do myself?