Still want to shoot into a thermal runaway.

have a compression test done as it appears that there is a head gasket or cracked head problem and the compression gasses are getting into the radiator.

Did you TRANSFER the Temperature Sensor over to the new Radiator and did you Plug it in?

There is a RELAY that you may need to test or you may have an electrical problem going to the FANS? Remember you had to remove the Fans to install the Radiator but you have to Plug them in when you get done..

Hopefully you did not pinch a wire along the way...

Well you could have a bad water pump that is not circulating the water right while you driving you car on high speed but if you wan to try if is the thermostat take off and drive the car like that if the problem goes away just put a new thermostat

(I don't know much about cars so bear with me).

I've had problems of overheating previously where my car's thermostat would hit 140. I think I've fixed the issue, I've replaced the thermostat but it was still doing that and 2 hoses blew and needed to be replaced. I've had to consistently fill my radiator with 50/50 antifreeze on a daily basis to ensure it won't overheat, so far that seems to be keeping the peace.

But now as of 5 days ago, I'm experiencing these new issues of stalling. Upon taking my civic into my mechanic, his meter showed that there was a misfire in the 2nd cylinder a month prior and now all 4 are misfiring. He thought it was the head gasket at first. I had just recently replaced the spark plugs with NGK Platinums, new spark plug wires and a new distributor cap.

I've received many possible culprits to my problem consisting of possibly the Throttle Position Sensor, Fuel Filter/Injection, Distributor or a radiator cap. I'm financially strapped at the moment and only could afford the radiator cap which didn't solve anything, however my radiator is running on 80% water at the moment. I'm really at a loss and I feel like I've done what I could and I'm at my wits end. Please help my poor little Civic cheat death for a little longer.

sounds like a blockage like a dodgy thermostat, id test it by boiling a jug and throwing your new thermostat in the boiling water and see if it opens, other than that you've pretty much done it all so id be looking at a blown head gasket. good luck :)

heat rises can be a number of things,, is anything blocking the air flow through the radiator, are the cells in the radiator blocked or clogged,, look in through the cap refill for the radiator and see if its rusty if so flush the radiator, is the thermostat the recommended heat range for the motor? Is the fan working correctly,, any of these could cause your problem, once it reaches the correct heat range is the thermostat opening and the temp0 drops,, and here's one that I have to add , but no reflection on your repair abilities, But I've done it ,, so I know it happens,, is the thermostat put in the right direction, make sure the spring section is towards the motor

Is the car actually heating up?Does the radiator boil?Have you looked at the temperature sending unit giving a bad temp.reading.?The thermostat needs looking at and also the head gasket.Hope this helps

Under the hood find radiator at front of the car on either left or right side of radiator is a fat hose that will be connected to the radiator. Follow that hose to the engine and it connects to the thermostat cover that is connected to the top of the engine with two bolts holding it on. Remove both bolts, Remove thermostat cover replace with new thermostat, Scrap off old gasket on both connecting sides place in new gasket (using a gasket sealer with the gasket wouldn't hurt to) replace both bolts only SNUG tight if using sealer let sit for a hour or two. your done!!

The upper radiator hose connects to the thermostat housing . Loosen clamp and remove hose from housing nipple , there will be two bolts one on either side of the housing remove bolts lift housing and thermostat will be under it ,pay attention to the way it is facing before removing . remove old thermostat clean off old gasket seal install new gasket (it will come with the new thermostat ) install new thermostat face same direction as the old one was. reinstall housing and hose . refill radiator with antifreeze let car run till it warms to normal running temp check for leaks on hose and housing tighten clamp or bolts if needed if no leaks your done. Hope this helps.

THE EASIEST WAY TO REPLACE THIS RADIATOR IS TO REMOVE THE FREON FROM THE AC SYSTEM, DISCONNECT THE LINES GOING TO THE AC CONDENSER, REMOVE THE FAN SHROUD TOP AND BOTTOM, THEN REMOVE THE 13MM BOLTS ON THE UPPER PART OF THE RADIATOR SUPPORTS. REMOVE THE AIR DIFLECTOR ON THE BOTTOM OF THE VEHICLE, REMOVE THE AIR FILTER ASSEMBLY. LAST YOU NEED THE TOOL TO DISCONNECT THE TRANS LINES. ONCE THIS IS DONE THE RADIATOR AND THE CONDENSER WILL COME OUT IN ONE PIECE. AFTER THIS IS DONE YOU CAN EASILY REMOVE THE RADIATOR FROM THE SUPPORT.
IF YOU DO NOT HAVE THE TOOL TO REMOVE THE TRANS LINES YOU CAN UNSCREW THE TRANS LINES FROM THE RADIATOR. YOU WILL HAVE TO REMOVE THE FITTINGS OFF THE NEW RADIATOR AND USE THE OLD ONES. ONCE YOU HAVE THE RADIATOR IN PUT THE FAN SHROUD BACK IN AND TIGHTEN THE BOLTS. THEN IF YOU HAD TO UNSCREW THE TRANS LINES DUE TO NO TOOL, REMOVE ONE OF THE FITTINGS OFF THE NEW RADIATOR AND SCREW THE OLD FIITING BACK IN AND TIGHTEN IT. THEN REMOVE THE OTHER TRANS FITTING AND SCREW IT IN USING THE OLD FITTING. DO NOT REMOVE BOTH OF THE TRANS FIITINGS ON THE NEW RADIATOR AT THE SAME TIME OR YOU WILL LOSE THE RESEVOIR IN THE RADIATOR. ONCE THIS IS ALL DONE EVACUATE THE AC SYSTEM, RECHARGE THE AC, FILL THE RADIATOR WITH COOLANT AND YOU SHOULD BE GOOD TO GO. I HIGHLY RECOMMEND REPLACING THE RADIATOR, THERMOSTAT, AND THE RADIATOR CAP AT THE SAME TIME. I BELIEVE THE THERMOSTATS IN THIS VEHICLE DO NOT OPEN AS DESIGNED WHICH CREATES VERY HIGH PRESSURE IN THE COOLING SYSTEM WHICH CAUSES THE RADIATOR TO FAIL PREMATURELY.
AFTER STARTING THE VEHICLE CHECK THE UPPER RADIATOR HOSE AND MAKE SURE IT IS NOT ROCK HARD, IF YOU DID NOT REPLACE THE THERMOSTAT. IF IT IS ROCK HARD REPLACE THE THERMOSTAT.
THINGS TO CHECK:
CHECK THE RAD/CONDESER SUPPORTS FOR CRACKS YOU MAY FIND THEY ARE BROKEN IF THEY ARE REPLACE THE SUPPORT. IT IS AVAILABLE FROM FORD.