[RufflesRidge]

The 4x decoding mode can have trouble when the phases of the encoder are not perfectly 90 degrees apart (most encoders aren't) and the encoder is spinning fairly fast. I recommend 1x decoding for the drivetrain. It should still give you more than enough accuracy. See if that clears things up at all.

Also, the stupid question, your encoders are attached directly to your wheels/wheel shafts right? Or a shaft attached to the wheels/wheel shafts by a 1:1 ratio?