My expedition dies right after starting . It is emitting white smoke and a strong gas odor from the exhaust . What is the cause of this

Hello, a strong gasoline odor and white smoke kind of contradict each other. Gasoline that burns raw through the exhaust typically will email a darker colored smoke. White smoke is the smoke of condensation or water. I have no reason to suspect that any water would be coming through your exhaust system with this particular engine and vehicle. However darker smoke color from unburnt fuel would be the result of an air fuel mixture issue or an ignition system misfire. Both are items that need to be diagnosed using engine performance diagnostic techniques, referencing a Ford workshop manual and using a diagnostic tool suitable for doing the testing needed. Your running symptoms mimic this also - so get the truck tested to find out what's going on! Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops