When I put a 5.0 pill in my light seems to come on right at 5000rpm. But when I put a 5.8 pill or a higher rpm pill the light doesn't come on. It can only tell when I'm really on the car as I don't rev it that high unless I'm moving. I always end up shifting before my light comes on. What's the deal, is my stock tach that far off or is there somthing wrong with my set up?? thanks.