Hcivic22

hey guys my names jared i have a 97 civic with a h22 swap and i was wondering if you guys could help me with a little problem with my car. when i'm driving and come up to a stop sign i put in neutral and the car will rev up around 1200-1800 then when i get to the sign and am completely stopped it will rev back down to normal idling what do you guys think the problem could be thanks!

Car: 1997 civic
engine: H22a
parts: skunk2 intake manifold, megan racing header, and aftermarket intake(no name)