I have a c6 grand sport century built 6l80e, 440lsx, ysi on around 17-18psi on e85. I have been fighting an issue for a couple weeks now. In auto shift mode the car never makes it to the wot rpm shift point, ends up shifting out on mph. It hits like 6200rpms and hits a wall, then drops 100rpms and back up and continues doing this and can?t make it through. I swapped plugs today and tightened the gap thinking it was maybe blowing out spark at that point. Just took it out on pump gas, and it?s worse now. Not it will not climb passed 5800rpms. I?m showing 0 knock as well on these pulls. Anyone has any ideas? The car has been tuned for a while and made 1007whp. So I?m not sure it?s tune related?