My civic one night started misfiring and after running the codes i got ones for a misfire in #1, #3 and a code for multiple misfires. My tachometer also started acting wonky. I replaced the spark plugs and it fixed my misfire on #1, but #3 was still misfiring. I replaced the cap and tested the wires as well. Haven't replaced anything else besides the spark plugs. Took it to a shop and they said that I have no compression on #3. I think it could be the ICM since it's already the reason my tachometer messed, but I don't want to throw money at it and if possible I don't want to swap the motor.

 

No compression on 3 is going to most likely be a burned exhaust valve.

 

I agree with this suggestion.

 

Do a compression test first (no compression tester? Autozone or any car parts place will lend you one)
more than likely its a valve as the others have said.
you have a couple of options here. sell/scrap the car and get another beater but with used car prices today that may be a bad idea. Take it to a shop to fix, Totally acceptable but financially you would be throwing good money at bad butttttt if you drive the car for 5 years without any major problems you would get your money back. Or lastly fix it yourself. "Oh no I cant do that, I dont have the tools or the knowledge to do that" HA HA HA (insert evil villain from a bad movie laugh here)
Go to Amazon, order the repair manual. After you read the manual, go to Harbor Freight and get the tools. Take the head off, either have the head milled flat and have a valve job done to all the valves, or just have the bad valve replaced, put it back together and drive the wheels off it
new head from Headsonly.com 350$
gasket set 50?
timing set 75?
oil/antifreeeze 30?
If you have no mechanical ability it will take you about a week to do in the evening after work
some mechanical ability will take about 3 days
the more experienced of us can get it done in a day.
Good luck with whatever you decide