The hunt is the engine getting bad input- the intake and coolant sensors may be faulty as you would have thought but the wild fluctuations are voltage related. If the engine stalls or almost stalls this is probably the cause of a sudden drop in voltage which may do that or upset the ECU or even the voltage the O2 sensor feeds it.

How old is the battery, O2 sensor and spark plugs?
Best to test the engine coolant temp sensor as they do fail... if it reads badly the mixture will be incorrect, the o2 sensor readings will confuse the ECU and the idle get adjusted incorrectly causing voltage drops and stalling perhaps.