Diyvehiclerepair
A vacuum leak, sensor that has failed, or an EGR system malfunction could potentially be the cause of the erratic engine you're experiencing. ... For this vehicle, the engines are very sensitive to vacuum leaks in the intake air tube, between the mass air flow sensor and the throttle body.
Why do my revs go up and down when idle?
If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
Why does my car keep revving up and down?
Car Revs Up and Down Causes
Transmission fluid is exclusive to automatic vehicles. ... As you speed up, this fluid starts to flow faster, lubricating different parts as it moves along. Any kind of leak in the line will make your car start to pick up RPMs, making it rev up as your driving.
