okay, Let me start off with my 91 acc. ex 4dr which is equiped with an after market header, muffler, high-flow cat, short ram intake, and an exceddy oem clutch; On the other hand, my brother has a 92 acc. 2dr LX that is equiped with an ex header and down pipe, aftermarket muffler, and short ram intake, and the car has been dropped. Well, when I drive his car his acceleration picks up fast and smoothly. My acc. has just a little lag in the low-ends, but up at round 60mph, my engine has no trouble increasing speed. when the two cars sit and idle, his acc.'s throttle is a lot louder than mine. Could it be that throttle is not adjusted correctly? or a bad intake manifold?