2007 328I OverHeating - Rmp fluctuation - Please help !

[Umermulla]

Hey I have a 2007 328I coupe with about 80K miles
The car had a loss of power and temperature light came on the highway, I had it towed n changed the thermostat , also had the coolant flushed ( there was a constant loss of coolant)
After that the car ran fine for about 2 days n I filled about 2 cups of water

The car over heated again n I got it towed to my house n now when I turn the car on the RPM fluctuates spraticly between 1500 and 500RPM just up n Down

Not sure what's going on Any thoughts would help!!

Thanks In advance
Omar

[Lord Vader]

What was the cause of the loss of coolant? Was their a loss of coolant the second time as well? Is their visible coolant leaks?

[Umermulla]

there were traces of collant on my driveway