1992 Isuzu pickup problems

I have recently encountered two problems with my pickup: 1. Upon the vehicle warming up, when you cut it off, it will turn over but will not start up. If you let it sit for about 1 to 2 hours, it will start
and run as if there was never a problem. I have replaced the fuel filter, mass air flow sensor, air filter, oxygen sensor, distributor cap, rotor, wires, and plugs. I performed a computer self diagnostic and detected no problems. I am inclined to believe the problem stems from the fuel pump but, having it occur only upon warmup and only after cutting off the pickup doesn't appear fuel pump related. 2. Upon applying brakes, I physically feel the brake pedal gradually losing pressure and sinking to the car's deck. Unless I pump the brake pedal 2-3 times to build up pressure, the brake pedal will continue to sink, and I will eventually lose braking power and roll forward. I have replaced the front disc brake pads. The rear drum brake pads do not appear to be worn beyond specifications. I have generously bled all brakes. Visual inspection of all brake components has revealed no leaks. I am not losing brake fluid from the master cylinder.
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shadetree via CarKB.com wrote:

Not a clue about #1 but regarding your brake problem, I would suspect that your master cylinder seals are going bad. It isn't leaking to the outside but is unable to hold pressure.
-=-=- ... Nothing is so simple that it can't get screwed up.
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