I took the Elk for a drive and the speedometer wasn't working properly though town and the country roads. I had pia new cable in awhile back. The first time after the installation the speedometer worked great. The second time I ran it in town not over 25 mph. That trip it had fluctuations between 20 and 25 mph. Today it got up to 20, when I stepped on the gas, it took a lot of throttle to get the speedometer above 35 and I know I was going over 35 by a lot. Where's the best place to check the cable first for problem to correct it?