This truck has 4.3 liter , v6 yes it is ,is driving me crazy, runs good in idle , no misfire , when is hot is ok , but when I start in the morning or when I left cool down there is no power and shut off some times , no codes present do you think can be the transmission , ECM , how about the catalytic converter? please help me boss is going to fire me if I don't fix this sucker. thanks dornier34.