When you let off of the gas, what keeps the idle from going below 700-900 rpms? I was having alot of idle problems and I got most of them fixed, but now all I have left is this issue. Say i'm driving down the road. Red light comes up, and I let off the gas. At that point, the rpms drop to like 300 ONCE, then it goes back up to like 900. B16 btw....