It's fairly common for fuel pressure to bleed down over time. That is caused by a leaking check valve in the fuel pump, a leaking fuel pressure regulator, or most commonly, a leaking injector. To find a leaking regulator, looking in the vacuum hose is one thing to check, but it can just be leaking back to the tank. You can find that by using a hose pinch-off pliers to pinch closed the return hose. You have to remove the fuel rail with the injectors to watch them to see which ones are leaking.
You didn't say what the starting problem is or how you get the engine started, but if you're looking for the cause of low fuel pressure, I'm guessing you have a long crank time before the engine starts. If that is right, you can overcome that by pausing in the "run" position with the ignition switch before you turn it all the way to "crank", or you can turn it to "run", wait a few seconds, turn it back off, wait a little, then turn it back on and to "crank". That will give the fuel pump longer to build pressure.
Wednesday, January 8th, 2014 AT 11:46 AM