I am at a loss for why my car pulls rpms right to 6,500rpm and then stumbles backfires and then has no power if revd.

The motor never shuts off but just has no power like it has fouled plug. If I do nothing and let it coast clutch in with the motor idling the motor will come back alive after a second or two. A little about the car and motor. The car is a S13 HB with a SR20DET. The engine is a rebuilt red top, extrude honed head, stroked crank and rods, with 9:1 pistons, 750cc RC Engineering injectors, Sard fuel rail, Sard Fuel pressure regulator, Freddy intake with smoothed runners, factory throttle body, EVO intercooler, Blitz BOV(re-circulated), S15 T28 turbo from Nissan, Greddy hard line intake tube, AEM ECU with 7,000 ignition cut, 3" down pipe, 3" straight muffler with down turn, Greddy Profec B-SpecII boost controller, NGK Iridium plugs with 27 gap.
I am at a loss why the motor cuts out at 6,500 on the nose.

If I try reving the motor the engine tries to run like it on has 3 cyl. Now if i just let it idle and wait a second if come right back to normal until I hit 6,500 again.
Any ideas on what I should check or try?
Please help!
THANK YOU