My brother in law has a 95 Chevy Silverado Z71 with the 350 V-8 engine and throttle body fuel injection. In the mornings on cold start, the truck won't idle and wants to die if you don't stay in the truck to pump the gas. After running the engine up to full temp the truck runs fine, but then after a warm shut down, the truck loads up with gas and smells of very rich tailpipe emissions. Again the truck wants to die and you need to open the throttle up all the way to clear it out before it will stay running. He's tried new fuel injectors, new fuel pressure regulator and a new air/idle control valve. Nothing has fixed his problem. Do you have any ideas?