My 92 civic with a crv motor dies after being hot and sitting for a while i.e. 20m to 3 hrs..
What happens is I can clearly hear the fuel pump running healthy when car runs well.. when the problem hit a loud humming noise will arise from under the dash the I lose pressure and car dies but can still hear the fuel pump but sounds like its cavitating... HELP Ive replaced the main relay, Fuel filter, Pump , and regulator..

The ECM may be intermittently failing. Perform the K-Test on the ECM:

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (Position II). Using a multimeter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it's probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate.

Sometimes, corrosion on the main ECM ground is whole problem.