Random cranks but no start, when it does start it runs runs rough and at high idle and blows black smoke

This happens anytime it wants either after running or after sitting just random it cranks but wont start. until i hit gas pedal then it starts but runs rough and at high idle sometimes up to 4,000 rpm's. also it blows black smoke when this happens. another thing that happens is the temperature gauge wont come up , after 5 minutes or driving it a couple miles the whole thing calms down and runs perfect and the temperature gauge comes up. i am at a loss on this one. Help!