Vapor lock is the running and motor is hot, then you sit for a while and it won't start. May get a cough every so often, but will not hit. You keep at it and after some more cooling down it will fire right up. Most vapor locks happen after sitting for about an hour or more.
Sitting for a long time and it won't start may be your anti-siphon valve could be allowing the fuel to drain back. The electric fuel pump does not suck very well at all. The older diaphragm pump can suck fuel up quite a bit easier. Not trying to talk you out of a fuel pump, but if you have good pressure after its running, then in most cases the pump is fine. The pump won't pump and then later get weak and then get good again.
Fuel pressure should be right at 40 psi, manual shows 43 psi running. A check you can do is get the motor running and after a few minutes shut it off. Install the pressure gauge and turn key to ON (don't start) and see the reading. Now watch it and see how fast it takes to start to drop. If it drops kind of fast it could be an injector or regulator. The pump may also be leaking but need to get a good picture of what's happening.
