My 2001auto gt is having an issue Im hoping to fix in the morning if we can diagnose it. The car will shake at red lights and has idle issues. The tach will do a sweeping motion as if the car is looking for a position to idle at. Then when I push on the gas the car stumbles unless I make the Rpms jump. I had a code for the driver side front o2 sensor needing to be replaced, and plan on doing that tomorrow, are these symptoms of the o2 sensor or something else? I'm thinking iacv is possible, opinions?