my wifes 2000 sunfire gt has started to idle a tad low,about 650 rpm,it allways used to be about 750 to 800 in gear,it drives fine but gets only about 380 km's to a tank of fuel.
o2 sensor maybe?also are all 2.4 engines a little mechanical sounding ,it just seems loud at idle like a fluffing noise.thought it was an exhaust leak but it just sounds weird at idle,could a plugged cat cause weird stuff because we had a tank of bad fuel and i think it may have roasted the cat because now when it gets hot it smells like sulfur,and yes i changed the fuel filter and plugs. thanks

650rpm is higher than mine. When hot the idle is at 600rpm.



Gilles
2.3 Ho