please help 88 n/a sputters hhard after 4500 at w.o.t

does any one know of any possible sources of this? i have an exhust leak but we are talking magor back pressure loss at wot and only wot soon as i hit 4500rpm please help thanks

exhaust leak could be related because the auxiliary ports (5th and 6th intake ports) on the 86-88 cars open with exhaust backpressure. so look into fixing that.

check this out:
http://www.aaroncake.net/rx-7/6porttest.htm