My speedometer bobs around at speeds above 60 mph. I also notice that the odometer is recording mileage at about 8-10% less than it should (I timed it using highway mileage markers). IPD catalog says to try lubricating the speedo cable. A) Where might I find the speedometer cable? B) If I fine it, what would I lube it with? C) If it needs to be replaced, is it a do-it yourselfer? Do I need a whole new gauge/console? Thanks!