I just bought a 93 rx7 and the car cuts out and misfires when i quickly accelerate and it reaches around 4000 rpm.
The previous owner says that the car has had this problem before and he took it to guy who cleaned the throttle position sensor and the car ran fine again.

Initially i tought that it couldnt be so i took the car for a diagnosis and errors 51 and 54 came up (air pump relay and fuel pump relay short or open) can someone help me on this?

I already changed the fuel pump and nothing changed, the curious thing is that if i accelerated slowly the rev passes the 4000 and can sometimes reach the 9000 rpm in neutral but if i'm driving and i use the same procedure it only goes up to 6000rpm.