What has the 60' and 1/8 mile times been. If your slowing down on the big end 3rd gear could be slipping. Slowing everywhere could be converter. I would drop the trans pan and see if you have debris. Band adjustment while you are in there.
And my mph are slower at every distance. The whole time after I launch it feels slow and not pulling or accelerating. Feels like engine is working but car not moving
