Not clear if there is a connection between the two, but the engine surges around 300 rpm at rate of about once per 2 seconds when feathering the throttle, and seems to have a noticeable loss of power from about half to full throttle. Surges when idling in park about 600 - 1000 rpm for a while and then settles to 700 steady. Check engine light is on and coolant level light comes on intermittently. Odometer is now 105K. Any ideas as to whats going on here?