Car wont start after initial trip

What is your question?

I have a 01 Monte Carlo and I have replaced the alt, fuel pump/filter and pressure valve. The car will start sometimes and sometimes it wont. If it does start once I turn it off and get back in it it wont start have to wait like 20 minutes before it will start again. There are no warning lights. Had a diagnostics scan and nothing showed up but the pressure valve. Fixed that car still does the same thing. It will also cut off while your driviing

How long has your 2001 Chevrolet Monte Carlo had this problem?

few weeks