Noticed and issue today while I was out toying around in my car, I tried to open it up all the way to see what's new motor would do and after my tach gets near the redline it just stops accelerating. If I'm moving about 60 and give it enough gas to get it moving like just passing someone it will accelerate but not shift down or up and go till I hit the lighter red part on my tach. If I stomp it after it stops accellorating, my car downshifts then come back up to the same spot on the tach. It feels to me like I'm missing a gear or its not up shifting. The motor feels like it has alot left in it

 

Could be many things. Valve float, air or exhaust restriction, Cam timing, ignition timing, air fuel ratio or something else. not sure