hi there, well...i have already replaced my knock sensor....cause i dont know why my sensor was killed but anyway, i saw that my car(radiator) leaking water from the plastic tank, so i think theres a lot of heat on the engine...i think my thermostad is bad....i will check it asap but do you think guys...the very high temp of the engine(if the thermostat is bad) can affect the gas mileage???

did you replaced the thermostat??? any suggestion?

 

The thermostat is designed to stay open if it goes bad. So, a bad thermostat will make the car warm up more slowly. I would check the the quality of your coolant. Make sure its 50/50 water/coolant. Your symptoms could also suggest major engine problems, too. Like a broken head gasket.

DW