Sometimes, Id say half the time if not more, when the engine is hot, and I try to start it soon after I shut it off, it will not start. It turns, but does not start. If I wait maybe an hour, it starts. I have found a solution for this, I press on the gas pressure release on the fuel rail. Gas comes squirting out several feet, then slowly flows out. I think the fuel pressure regulator might be malfunctioning, but why does it only happen when the engine is hot? Maybe it could be useful to say that I forgot my fuel cap at a fuel station, but I dont know if it could affect it, I think it did it before as well.

replace the regulator first if it's not too much hassle or costly.

Fuel filter maybe?

before you go replacing things all willy nilly, be smart and test it.

When you pressed on the schrader to release the pressure, was your key on, or was it sitting idle.  the sytem will hold pressure and then when you press that it will release it, if the fuel pump is not running you just let out all the pressure so it will do exactly what you described.

First, get a new gas cap, this eliminates this as a problem.
I would check and make sure you have fuel pressure as you crank it.  If you do, this removes fuel pump, pressure regulator and Fuel Pump relay as possibilities.
If you have fuel pressure and everything is good at this point, post up with what pressure you have and any other anomolies you have noticed and we will go from there.

Clogged injectors. 

You can check the Impedance on the injectors that will tell you if they're just plain out failing but it won't tell you if they're clogged.

If I remember right, the 95's were the only ones that did.

I could be wrong though, I will have to look into it.

First things to check in this case are, fuel filter and fuel pressure.

If you have pressure built up in the sytem the filter could be clogged and the pressure is holding the sediment in place, when you relieve the pressure it allows the sediment or whatever to flow back through the line and removes the clog.

I would still stick a pressure gauge on it and make sure you are getting correct pressure at the fuel rail, pumps can start to go out in warm weather and the sock could be clogging up.  After that I would check the FPR, of course the pressure test should give you some hint as to if that is it or not. 

Also pour in injector cleaners are great but remember the dissolved crap can only go one place, and that is through your fuel system.  I would recommend paying the $70-100 to take it to an ASE certified shop and have them clean it for you.  They will run a pressurized cleaner through it and keep it from staying in your system or going through your injectors.

Let us know.

Mine does not have  a return line.
It should come off the opposite side of the fuel rail that the pressure line goes in.

DT, my car is an hour and a half away and every time I go to see it I get in trouble for now because of other things, so no... not so much go check it out.