high speed engine studder 89 rx7

[attrendive]

just wondering if anyone knows what could be my problem? when i get into 4/5th gears my car studders like a bad coil only every thing in that area has been changed. plugs, wires, coils!! i was thinking injectors but im not sure? any help would be appreciated

 

[UnNaturalinc]

Could be injectors.... how many miles are on them? It's like $100 to have them cleaned and checked by RC.

Is it when the car is under a load when it does this? Perhaps the turbo has something to do with it....?