I just solved a problem in which my engine didn't like to start after sitting for a couple
hours.

Turned out that the fuel filter was leaking.  A lot.  But fuel evaporates really fast so
there was no puddle.  The fuel leak depressurized the fuel system, and it seemed like the
car was having a hard time starting when in reality, it was just waiting for the fuel
system to pressurize.  I only noticed it when I left home, forgot something, came back,
ran into the house, ran out, saw the puddle.

I replaced the fuel filter...all is good again.

...Markus