cant go past 5000 rpm

[91 240sx kid]

I have an r33 but its not running at its fullest when i start to excellerate the car goes fine but as soon as it hits about 5000 rpm the motor starts to spit and the car looses all of its power I dont think its a missfire because the car idles ok.

[crazyandevil05]

check coil packs. mine did the same thing. it would idle fine, ran fine until just after boost hit. the coils were just ok enough for normal driving, but when it crossed a certain thresh-hold, it would mis-fire and spark right then. cant remember how to test them, but i remember when i did, they seemed fine, because the voltmeter wasnt putting enough electricity through to make them miss. ended up just getting all new ones. but in hindsight, i have heard you can fix (not sure how long it would work) by wrapping electrical tape around them.