Why does my car rev up and down at idle?
Why does my car rev up and down at idle? Over time the throttle body valve can become dirty which can allow the throttle body valve to stick or not open/close all the way which can cause your car’s engine to rev erratically and can cause the engine idle to bounce up and down. What are the symptoms of a rough idle engine? It is possible for you to test the EGR valve at home, using a hand held vacuum pump. Other symptoms: An EGR stuck open may include a rough idle, rough performance at low engine speeds, stalling at...