Q: Please make this quick, I have a misfire on cylinder 3 was told to change the ignition coil. What if my car runs extremely good.

Hi there. For the coolant light being on, check the coolant in the radiator and see if its low. If the fluid is low, then look around for any possible visible leaks. If there is no coolant leaks, then either the coolant is boiling out the overflow tube or the coolant is being burned on the exhaust system with a leaking freeze plug.

If the engine is running smooth with a misfire, then either there is a fuel issue or a spark issue. If the coil pack was replaced, then I recommend putting in new spark plugs if they are old and white in color. If the spark plug is wet with fuel on it, then either the plug is not firing, the coil pack is not firing, or a fuel injector is leaking. If the spark plug is dry, then there could be a plugged fuel injector causing the cylinder to not fire from the fuel injector not working properly.

I recommend changing out the spark plugs and performing a fuel injection flush.

If you need further assistance with your engine misfiring, then seek out a professional, such as one from Your Mechanic, to help you.