I am driving down highway at about 60 and I notice multiple times my speedometer with fluctuate down to 45 and then back up to 60. This is also accompanied by a warning tone, ABS light, Brake light, traction control light for a split second. There is no shuddering or anything else. This also doesn't appear to happen at low speed. The only thing that has been fixing this car is the front wheel bearing and I changed out the positive battery terminal. But it has been a couple months since those have been replaced. Any suggestions on what might this might be?