Could be running super lean. That would be my guess. That's how my vortech kit was when running lean before getting a tune with aem ems.

 

We have the same setup, well had until i changed my pulley out. With that black box, Mase put my car on the dyno and i made 320 hp to the wheels at 7.5 psi. Thats the stock pulley. I just put a 3.8 on now. But when we checked the plugs, he said that there was too much timing in it still. So if i was you, i wouldn't beat on it too much. And what plugs are you running? I'm running the plugs that he uses with his turbo kit.

 

I'm using the stock ngk

 

Should get some "2668" I believe one step colder NGK plugs.