Sometimes it reads at 13, other times it reads just above the red. It doesnt matter if any accessories are on or not, just sometimes driving down the road it will jump up if it has been reading low, or go down when it has been reading normal. I have hooked up my battery/charging system tester and it reads between 13-14 regardless of where the guage is reading. any ideas???

 

Bad gauge? I've heard the stockers were never known for thier accuracy anyway...