my car wont turn on damm any body can help me i check everythiong is gud fuel main relay distrubutor wire spark plugs act

 

i check the distrubutor change the main relay i check the fuel presure i change the coolant heat sensor i spark plug wire and sparkplugs the car cranks but it wont start unlesss i crank it alot then the car works find but if i llive it off for more then 30m it loses the spark it wont turn on