I just baught a 1990 Honda Civic and I drove it around for a few hours and when I got it on the freeway it went for a few miles and then started sputtering and then just shut off. Does anyone know what would make a car just shut off?

Read sections A and B, in the link below:

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

First, make sure to answer the 3 basic diagnostic questions. If you can answer "Yes" to each question, focus on the Ignition Control Module (igniter), inside the distributor, and the coil. Because of the age of your Civic, both of these items really should be replaced, since they are so problematic.