You smell gas, is it coming from the engine bay or the exhaust?

With it being an efi engine it is damn near impossible to flood it, injectors are either on or off. However, one or more of the injectors or the cold start injector may be leaking fuel w/the engine off, or dumping fuel upon start up.

To see if the system is leaking fuel w/the engine off, crack the gas cap to relieve pressure from the line, or crack the fuel line at the cold start injector.

If that doesn't help any, pull the plugs after it sits a while, and turn it over a few times, if you get a good strong smell of gas, it could mean that the injectors are dumping fuel on start up.

Usually injectors clog up with age, but yours could be dumping too much gas.

Any significant decrease in gas mileage before this started? Does the engine and truck run normally after it starts?

Hard sputtering start when cold can also be a sign of a bad head gasket, any loss of radiator fluid taking place?