I have a 1989 accord that was running great until it starting idling strangely after the car warmed up... the idle would fluctuate up and down but would stop after a while.

Eventually it started idling rough all the time and then one day it just would not start.

The car will run and drive but then will decide not to start and may not start for a couple of days at a time.

I think it might be connected to a problem with my electronic air control valve (eacv) but am not sure... how can I figure this out and what can I do about it? Thank you

. 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

. Clean the Idle Air Control Valve (IACV):

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-7.html#post1054149

Afterwards, clean the air box with a damp rag and replace the air filter.