HELP!! 1991 honda civic, 4 door manual transmission... this is my sons car... starts up and pushes the gas pedal and it dies... enough gas, just changed the fuel filter and oil... my husband thinks it is the fuel pump... what do you think?

Perform tests in Sections A and B below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563.html

Go over the electrical system and check the spark plugs (NGK only), rotor, and distributor cap. I suspect the Ignition Control Module and/or coil may be bad--AutoZone and O'Reilly Auto can test these for free. Because of the age of the car, I would replace them. Here's how to replace the ICM and coil yourself:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-4.html#post265896

Incidentally, I have never seen a bad Honda fuel pump, even though many people replace them. Further diagnosis usually reveals the problem is related to a blown fuse, bad ECM, or failing main relay (cold solder joints). If the problem persists, check/replace the main relay.

The most problematic components on Hondas are ICMs, coil, and main relays--I would focus there.