So I got the new pulley on and as expected 6* of KR on a 3.5. Its also running an LTFT of -10% at idle. That means that the car is running really rich right?

I also have noticed that i hear a hissing sound when i turn off the engine coming from somewhere near the manifold for a few seconds. Almost sounds like pressure escaping.

What could be causing the car to run so rich, that i can realistically troubleshoot?