I haved a 91 Honda Accord and it starts fine at times. Once the car runs for about 15-20 minutes and I shut it off. It will not start back up immediately. S light under water temperature gauge flashes. If I spray starter fluid in breather it will start up. Otherwise I have to let it sit for ab out 15-20 minutes and it will restart. Changed coil, plugs, computer. No luck in fixing the problem so far. What you think?

. 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

. Replace the main relay, which is located under the dash, left of steering column (hidden by silver cruise control box, which needs to be removed).
Turning the ignition key on and off will help you locate the main relay, by allowing you to hear and feel it "click." Main relays often have 7 wires going to them.

These problematic components should be replaced every 120,000 miles or 10 years, whichever comes first.

Changed the main relay also. Still having the same problem. What you think?

Did you change the ICM and coil? ICMs are the biggest culprit of all.

Have you checked for codes?