96 dodge 1500 hard to start

Well I fixed an overheating problem with a new thermostat!Yaaa! Truck started great int he morning, but as soon as it warmed up it decided it did not want to start or so I thought. If I crank the starter and hold it, it will eventually fire up. It does bang and ping irradically but then finally catches with a roar of the engine(?) I popped the hood and heard an awful sound while it is idling crazily, it is a load hissing noise that goes away once the engine calms down. There is also black smoke coming out of the tailpipe, however it stops once the engine calms down and starts idling properly. I know this is long, sorry. Any suggestions on what to try? PCV valve already checked