If you only installed the shift light without a tach you're probably thinking the light is off at higher RPM's when in reality your honda tack is off. After I installed my combo I thaught my tack was off by a few hundered RPM's (More in the upper RPM range) but I got told by many people factory tachs can be off by as much as 500 rpms across the range. This is why some people confuse redline and fuel cut off when they're the same thing. like my tach shows 6,800 when my Honda dash shows 7,200. Now if you're off a lot then you might have the 4, 6, 8 cylinder selection off.