Not Starting when hot on 1997 Saturn SL2

My 1997 saturn does not start after I have driven it for awhile, shut it off and try to start again. After it cools off it will start. Any suggestions?

Asked by for the 1997 Saturn SL2
Check the fuel pressure after the engine is shut off. It should hold pressure or the fuel system will get a vapor lock and be very hard to start. Refer to the Saturn repair information on the specs for the pressure and amount of time it should hold the pressure.
how do you chewck the fuel pressure and what would cause it to drop and get the vapour lock? what is failing? I have changed my filter and map sensor so far.
its your battery or alternator trust me