Mopar Orange Box with Tach

I've been having a continuing problem with my ignition. It turns over but no start ever once in a while. I swapped out my FBO box to my Mopar orange and while it hasn't had a no start, it makes my tach needle bounce around at 2500. It works fine from idle to 2500 rpm. With the FBO box it worked like it's supposed to.
Anyone have the same issues? How did you fix it?