Q: Car flashes "coolant temp/coolant level" light. Coolant temp GAUGE reads NORMAL!!! All fluids are OK! Temp light eventually goes out and about one minute or so later arcing (or a relais) can be heard from behind the glove compartment (the PCM I presume) and the engine will commence to misfire and jerk violently (almost like being turned off & on repeatedly). It eventually dies completely and can't be restarted until it has cooled down. The OBD-II codes are 300 and 336 which indicate a 'random misfire' and a 'crank pos sensor' error.
I'm guessing at a temp sensor shutting the engine down - but if this is it - why would there be no code in the OBD?
A: On newer cars the computer controls just about everything that can be. Your problem could be a malfunctioning coolant temperature sender. You can check this with an Ohmmeter (if it's an electronic sender) by sticking it in a pot of hot water with the tips of the ohmmeter touching the prongs of the sender. If the needle moves smoothly the sender is working but if it jerks or doesn't move at all your sender is broken and you should replace it, this could be throwing the computer off making it think that the engine is overheating when it's not.