Car will start up and run fine for about 20 min. Then idles low.

What is your question?

When you kill it it floods and wont start again until letting it sit for ample time. I have replaced fuel pump, filter, regulator, spark plugs,air filter.and cleaned the MAF sensor I checked the return fuel line and there is no blockage. Did fuel system pressure tests, and all tests are within parameters for this vehicle. Any ideas?