Ok so I bought this 98 Civic with only 54,000 miles from an older lady about a month ago. I have since changed out the ignition cylinder (key was getting stuck) hence low miles. Fuel filter, spark plugs, wires, cap and rotor. Diagnosed the A/C problem and got lucky and was one of the o rings on the condenser.
Everything was great other than an exhaust leak up until about 5 days ago.
I should have added this to my list of initial fixes, but two of the three belts completely shredded off.
I quickly parked the car and made sure it didn't run hot.
Now I did fail to mention that the idle position sensor p1508 I believe was throwing a code. So it would surge and idle weird up until I put it into drive. But I don't think this has anything to do with the misfiring
So I change out all three belts and I start getting this crazy misfire. And would now run hot. It would run and idle normal at the very start but when it warmed up it would go hot, then start running bad / misfiring.
So I removed the thermostat and still it will want to run hot.
I dont see any radiator fluid anywhere, and God help me but I don't think the head gasket is blown.

I check the obvious. Everything looks normal other than the injectors are pretty gunked up. I cleaned them and still has a misfire. But isn't throwing any codes.
As of right now it will start up and idle fine until it warmed up and it'll start climbing in temperature and running bad no codes are getting thrown, even though I haven't replaced idle sensor.
Is it some other sensor ?

 

Misfires and no codes? I would go through the grounds and see what you get after.

 

What is an idle sensor?