1987 Chevy Camaro 2.8L hesitation

I have changed fuel pump/filter, air filters, distributer cap, rotor, wires, plugs, timing chain/sprockets, checked the IAC valve, cleaned throttle body, checked EGR, checked coil pickup, and fuel pressure. The fuel pressure was checked at idle without disconnecting the vaccum line from the fuel pressure regulator and it read 35 psi. The car runs great at idle until you put it in gear then it will not rev and there is no power. Shut it off and let it sit for a while then it will rev again in park but put it in gear again and try to rev and it will not. car will shift so not torque converter lock-up. PLEASE help I am out of my league, can't figure it out.