The driver who fatally struck a cyclist and injured four others in a horrific Harlem crash was allegedly high on PCP and has a long history of vehicle crime — including driving while intoxicated and hitting pedestrians, law enforcement sources and prosecutors said Friday. Kevin Crosby, 49, of The Bronx was charged with manslaughter and driving while high after allegedly plowing into two cyclists and dragging them under his car Thursday night, according to police and witnesses.