92 pickup 3.0 5 speed runs great when weather is cold but awful when weather warms up. When the temperature gets up above about 60, it has problems wanting to start, and when I give it gas it sputters, wont speed up, or loses all power and seems to shut off. When I take my foot off the gas it goes back to idling normally. I'm not a mechanic and have no idea what to make of it. I was told it may be the cold start valve but not sure how reliable that source is.