STOP STOP STOP…Hondas are one of my specialties…Been working on them since the mid 80’s
YOu have one of the most common issues on fuel injected Hondas…ITS TEXTBOOK…
You have a problem with your AIR IDLE CONTROL VALVE…you may have unplugged it when doing your gasket for some reason…it is either unplugged, dirty with carbon and needs to be removed and cleaned OR you have air in your coolant system and it needs to be burped (most likely)…or the AIC valve failed (not too common)… Unplug the electrical connection and reconnect it to AIC valve. Did you open or provoke a coolant leak in your gasket replacement…IF SO…thats where your air bubble entered the picture.
THE AIC IS YOUR ISSUE…it needs what it needs to work…coolant bubbles will NOT be tolerated whatsoever and is BAR NONE the most common issue…
You can look up AIC valve tech support on the net…its all over the place in Honda forums…they deal with and fix this DAILY
Make sure your coolant is full and with NO bubbles…I think the civic had a bleed nipple on the coolant system near the thermostat housing BURP your system FIRST. If that isnt it…then clean your AIC valve of carbon buildup…if the slider cannot move back and forth from carbon it needs to be freed up so it can control your vacume leak ( I dont think you need to clean it…still want you to check for air bubbles…THIS IS BY FAR THE MOST COMMON REASON FOR AIC TO ACT UP… I am leaning strongly toward the Air bubbles in the system…because you are getting surging…if you unplug the AIC valve this is exactly what you will get. GO thru the checklist…and you will find the problem. DONE…problem solved. This is perhaps the one and only MOST common Honda issue…I have repaired HUNDREDS OF THEM…no problemo…its EZ and works everytime.