1993 Ford Bronco engine starting problem

I have been driving a 93 ford bronco with a 5.8 liter windsor for years but in the past year it has become harder and harder to start when its warm. It starts rather good when cold (does crank over twice during the turn of key before starting) when engine is at operating temperature and is not started right back up, after about 30 min of sittin with motor off it refuses to start. It just cranks with no attempt of starting for entire first crank then it hesitates but will usually start second crank any help would be great! Thanks