Ok, '91 Silverado, 5.7l v8 Recently (within the last week) when the truck has sat over night, I turn it on, and it is very rough and knocking....I give it gas and after about 1 min, it will settle down. I start it while warm, and it is fine. Only does it when cold. This video this guy did of his truck http://www.youtube.com/watch?v=W9366p80KOg Is what it mine sounds like when cold, when he goes to the side of the truck w/ the camera. His repair turned out to be the MAP sensor tubing/hose. I will check mine... Just wondering if there is any other ideas?? I have recently done a rebuild on the TBI, so I don't believe it is a leaky injector.