Can a bad Torque Converter cause eratic Idle?

I just had a used LT1 put in my car and upgraded to a Hotcam w/springs and kept the stock 1.5 rockers and also had a rebuilt 2800 stall put in all at the same time. The car has never really run good since the install, by Idling really bad to where it wants to stall out and throughout the entire RPM band it kinda hesitates and Im thinking its in part to a bad tune, or a bad stall converter, but just curious if that is a symptom of a bad converter.

I guess you could take out the transmission and run the engine and see what it does, but it sounds more like it's engine related to me.