Pontiac G5 Check Engine Light

When Idling, And Apparently Only When Using Regular Gasoline, I Notice My Car Pulses Back And Forth Almost, As If The Motor Is Having...

Check Engine Light Came On And Brought It Into Mechanic Who Scanned And Said The Rpm's Were Going Crazy. Idle Was Rough And Sounded...

Hi, I Left My Lights On And My Battery Died So I Had To Get A Boost From Bcaa. Since Then My Check Engine Light Has Been On. What Could...

If I Have Replaced The Sensor In My Pontiac G5, And The Engine Light Is Still On And Coolant Is Reading ............(no Temp.) What Should I...