89 GXL (S5 NA). <10k rebuild with streetport. MS intake, RB headers, RB presilencer. new: fuel pump, afm, pressure sensor, tps. problem came on suddenly.

During WOT, car will not rev past 6.5k without leaning out like crazy. Car is solid in high 11 to low 12 afr, then hits ~6k and starts leaning out and breaking up.

Can this be injectors?

Thanks for any help!