Your ABS speed sensor has the important job of reporting to your vehicle's ECU what the wheels are doing so that your vehicle can respond to abnormal traction or strange speeds with the appropriate action. Unfortunately, if your ABS speed sensor is gummed up, it'll send the wrong information to your vehicle, which will then do strange things in response to the ABS speed sensor's readings. If you can't clean your ABS speed sensor, then you need to replace it with a quality part from AutoAnything.