My 1998 accord lx is shutting itself off while driving down the highway. It's happened 4 days in a row now. Twice in basically the same spot (about 6 miles of expressway at 60mph) The next day at about 3 miles of expressway speed. First time it started up in about two minutes, second time it started as soon as I came to a stop, shut it off and tried it. Both times I was able to drive the rest of the way to work, and back home, without any problem. The third day it wouldn't start for about 20 minutes, but when it did it was okay, however it died on the way home. Funny part is, I can drive it all over the city, at 30 - 40mph, all day long, and have no problem at all!
I'm thinking its fuel or fuel filter related. Could it be the fuel pump is working to hard and a sensor is just killing it until it "cools" down? Any ideas?

Replace the Ignition Control Module (ICM) and coil:

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

If the problem persists, replace the main relay, located left of the steering column. Turning the ignition switch on and off will help you locate the main relay, by allowing you to hear and feel it "click."