I have a 93 Del Sol Si with a 1.6L that is loosing fuel manifold pressure when it is parked. After parking more than 1-hour I need to cycle the ignition switch several times to re-prime the fuel manifold and it will start perfectly. The fuel pump is functioning with each cycle of the ignition switch. I have verified that the fuel manifold pressure bleeds off slowly. I'm not thinking leaking injectors as there is no black smoke when it starts. Will replacing the fuel pressure regulator fix this problem or am I barking up the wrong tree?

 

Fuel manifold pressure?

First of all when you turn your car on, just before starting you should hear a hum that lasts a few seconds and then it stops with a faint click. Thats the fuel pump priming the lines etc..

If you feel that you need to prime it a few times before attempting to start then it's an issue with your fuel pump most likely.