I've just bought a 1996 RX7 with a stock drivetrain apart from HKS pods and HKS cat-back. Ive been in love with the FDs for a while but know little about rotaries (or cars in general really - but I want to learn!). Currently, serious acceleration starts at about 3000rpm, then at about 4500-5500 is very flat and hesitant, then it smooths out again above 6000. Any ideas what could be causeing this????

 

Do you have a boost gauge? You need to find out what your boost pattern looks like. Sounds like a problem in the sequential turbo system. Probably a vacuum line came off or one of the soleniods are bad. Most likely your secondary turbo isnt getting spooled up properly and at the 4500 transition the boost drops down real low. It could be a bunch of things really, but I would check your boost pattern first.