I just got this car a couple months ago. It's a 2000 Honda Civic LX 4 door sedan. I didn't start having these issues out of it until about 3 or 4 weeks ago. The car is equipped with the D16Y8 SOHC engine. The car does have about 240,000 miles on it.
Today I started the car to the same cylinder 1 misfiring. Maybe even 2. After 5 seconds or so the car with idle up and the misfire goes away. Before it would only do this on a cold start. But now its happening after 5 or 10 minutes of sitting. New plugs and wires, checked the cap and it looks really good.
Today I was sitting letting it idle after I got gas and noticed that my temp gage was up higher than normal. I refilled my coolant resovour hoping maybe it was low and just needed some. But that didn't seem to help. I wanted to see if maybe it was just reading wrong, unplugged the sensor and plugged it back it but back to the same spot. I wanted to see if it was really over heating so I turned my A/C on and it shot up super quick. The fans are kicking on and off as normal. If it'd the water pump I'm probably just gonna sell it and get me something different because I know they aren't any fun.
I'm starting to be lead on by a bad head gasket and if so. How should I go about this. Another thing. I also was really watching everything and the car has never gotten warmer than 1/4 mark unil today. It shot up over the half mark and stayed. While driving it did go back down but still was higher than normal.
Please if you have any clues to what is happening or have had the same problems let me know. Anything helps. It could be completely fine and the sending unit is going bad. Just kinda wierd because this wasn't happening before.

 

Don’t take this the wrong way but….Sounds like you’re not mechanically inclined to do any work. Just sell the car. The car seems to have more issues than you’re able to tackle yourself.

 

Okay well the over heating issue is fixed as far as I could tell. Open the rad cap and filled it back up. I've had it idling for around 15 minutes now. I don't know why it used or leaked coolant tho.

 

coolant doesnt just disappear, it went somewhere, could be a bad radiator cap, leaking headgasket, bad water pump seal. It went somewhere, now to find out where, google radiator pressure test and do it. let us know what the results are

 

Well I bought the car used, and before it had been involved in a car accident. So maybe it wasn't refilled with the proper amount.