Just got my 383 running and noticed that I have a miss or stumble under load only. Crusing or higher rpm accelerating seems to be fine. Plugs (gapped to .035. Nitrous/boost setup), wires, coil and opti are all new with rebuild. No vac leaks. All the wires are on all the way and none of them burned on the headers. What I was wondering is could it be possible that the miss or stumble is caused by something in my tune? Maybe a fueling or timing issue? Using TunerCat, so I can change things at will if needed. My A/F's are good while crusing. BLM's are solid at 128 and my wideband is reading 14:1 while crusing and it richens up when I gas it. Just looking for suggestions before I start tearing into it more this weekend. Thanks in advance.

Ken R.