Q: Engine idle fluctuates and dies.

This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. Since this valve is controlled by the vehicle’s computer, it will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed. The loss of coolant may suggest you have a leak somewhere in the cooling system. The fact that the oil is not milky colored and there is no white smoke coming from the exhaust is a good sign that you do not have a blown head gasket. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your idle air control valve.