1999 Chevy Astro Chevy astro problems

Hello I have a Chevy astro 1999 with 165,020 miles I have problems starting in the morning and sometimes in the after noon. While the van is park for a while, I try to started but it will only crank the engine. I had done everything check for spark and fuel pressure. The furl pressure I recieved while the engine was cold was 45psi but after the van runs the pressure will go up to 60 to 65 psi. I had change the spark plugs, wires,rotor, distributor cap, and some other like change the belt,pulley,thermostat. I had replace the Fuel pump like 3 or 4 years ago. What I had tried in the morning when is cold I spray some Carburator cleaner into the throttle body plates and it will start with no problem. I really need help??? thanks