It's a problem many may not know they're experiencing until flashing lights in the rearview mirror tell them otherwise. How do you know if your vehicle is reading an accurate speed? And if it isn't ...

Your car once had a rock-steady speedometer needle, but now it’s wandering a bit — or a lot. Maybe it’s not indicating any speed or it’s showing 60 mph and you know that can’t be right. “An easy way ...