I was having that problem myself. It was because of the BBK Plenum that I installed. For some reason, the plenum I got didn't seem to line up perfectly with my BBK 70mm throttle body. I also had a lot of slack in my throttle cable. I removed the Plenum and everything is fine. I will have to take this plenum back to the place where I purchased it and exchange it for another one. Maybe for the C&L piece.