wow its been a while, if you look at the intake manifold it has a tube off the trhottlebody that goes across the motor. in the middle at the rear of the engine is a black box attached to the tube. its an air silencer. it makes the intake quiet. basically it means it interupts the air flow to the throttlebody. take this out and plug the hole and now you have more air to the tb. more air = better performance. the engine is an air pump so when you do a cold ait kit or ram air and the stuff in this writeup its a good idea to upgrade to a 2.25" exhaust.

1995 nissan maxima se, 5spd short throw, aluminum flywheel and crank pully, stage 3 clutch, custom ported top end, full 2.5 exhaust jdm front end