help!!!rev limiter comming in 6k in forth

i have a 95 gsr,and all the sudden my rev limiter feels like its commng in at 6000 rpm,,i have a p72,im thinking that might have someting to do with it but i dont no,,it only does it in 4th gear at 6000 grand,,i dont no why it wont let me go above that any more,,any one no what the problem might be??

you will know it if its your rev limiter, you need the right ECU for whatever motor you swapped in.

its never done it before,,it just started,,it has the p72 for the gsr motor,,and i have a gsr,,so everything should be correct,,i just dont no what the deal is