Background: Original owner replaced engine 25,000 mile ago (through firstone).Our daughter purchased from owner 2 months ago, started overheating, diagnoised and replaced head gasket (thank you all).
All fine for next 200 miles.
Now: car will idle normal 4-5 sec, can hear click and CEL comes on, engine starts to die, comes back normal after second, idles normal, this repeats 8-10 times, then CEL light stays on, tac goes to 0, car will not go more than 40-45 mph.
Alternator produces 14.5 volts on battery, however dashboard indictor light comes on and stays on. Fuses have been checked.
I have been reading questions and answers, but have failed to find answer.
Also, hubby has not found the Main relay on this car?
Thanks so much,

. Check for codes--this will be the key.

. Replace spark plugs (NGK only).

. Check under-dash and under-hood fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post252145

Don't remove and look at fuses.

. Check idle speed, if the alternator light comes on.

I don't think your Civic has a main relay.

Quick response, very helpful info. Thanks so much