Poor Starting Honda Civic. Help!

I have a 2006 4DR LX Honda Civic, and the car is still in warranty. But every few weeks or so without warning the car will not start. It won’t even turn over, or attempt to turn over. The dash lights blink on for a moment and then die as I try to turn the car on. We tried to jump it and nothing happens. The next day the car starts fine. My car dealership is puzzled. They’ve checked the battery, the ignition and they claim to have checked the wires and such. They also called the Honda tech support. Does anyone have any other ideas that I can give my mechanic? Any help would be appreciated.

Without knowing if they did this or not, my first step would be to actually remove the battery cable ends and clean them.

I also have on idea how they tested the battery and it’s always possible for a battery to fail anytime no matter the age.

The battery should be put on the charger for a minimum of 30 minutes (prefereably an hour) and then load tested for 15 seconds to approx. 3 times the normal starter amperage draw.

When it does not start or do anything at all - do the headlights dim noticeably?

If so, the starter motor is drawing power but not turning.

If not, the starter solenoid is not engaging the starter motor. This could be because of a defective solenoid, or an ignition switch that is not completing the circuit to the starter solenoid.