Overheating and misfiring

[alms24sebring]

A buddy of mine's 92 hatch was overheating due to a leaky waterpump. One day he pulls in front of my house because it was misfiring and overheating really bad and shut off on him. He also said the needle was at or close to the H at that time.

So, the waterpump, thermo, radiator, and hoses were changed. But now the car keeps misfiring alot. The plugs are new and doesnt always misfire, but it still happens almost normally and when trying to rev it. So my question is that why does overheating cause a misfire? Ive always had it happen to other cars too until it went away. Is it a fried head gasket or rings? No compression test yet and he says that the plugs are dry. What else causes it?

Also on a side note, I hate trying to bleed a KA. Its so freakin difficult. The coolant keeps boiling and erupting out the rad when it starts to get hot. The front end has been lifted and its been bleed numerous times with the funnel and through the bleeder. Any suggestions? Would it have something to do with the misfire?

Thanks for any advice

[Towncivilian]

If you haven't inspected the radiator cap yet, see this TSB for examples of a bad rad cap. Replace with a new OEM one if necessary.

[Armstec_S13]

People never think about the little things, especially when they replace things for the cooling system after overheating, did he replace the CTS? (coolant temp sensor) usually malfunction after the car over heats, it will cause your car to run too rich and also cause it to run too lean, what happens is the sensor thinks the car is still cold so it tells the ECU to dump more fuel in like if it was in the cold start warm up cycle.... It's a red 2pin connector it will be next to a black single pin connector the black one sends signal to the gauge cluster and the red 2 pin is the one that tells the ECU the temp so it can adjust the idle/fuel/air flow, easy way to test is, start the car, go under the hood and disconnect the 2 pin red connector and see if the misfiring stops..... Hope this helps

[alms24sebring]

^^ The cap did sound like it was leaking air and I thought about that. But while bleeding it with the cap open, it explodes out.

^ Yeah I guess its a cheap $2 fix-it attempt. I guess I should add more detail. I didnt do the work, I was only helping to bleed it but this dumbass guy that thinks everything is Universal put purple coolant meant for heavy diesels and semi's in it. Not sure if that makes a difference but its not the same as green in my mind. Not only that but he only had a gallon of it and since it keeps boiling out, we have to keep adding water. Now its almost pure water and I can feel it boil in the upper hose and it still explodes out. I told him to drain the rad and do it right with green coolant. Who knows if the thermo was even put in right...

Anyways I guess I still dont know why it would be misfiring. Im glad this isnt my car lol. This is why I bought a Civic because KAs are impossible to bleed