My warning lights (brakes, ABS, transmission mode arrow, traction control, and check engine light) come on periodically. Not all at once, but between one and three at a time. Sometimes when they are on, the speedometer drops to zero and then mysteriously comes back on. Turning off the car will sometimes correct the warning lights being on. Some times they just go off by themselves. Once in a while it causes the acceleration to bog down. Occasionally, everything is fine and there are no warning lights on. Any ideas on what it might be?