So let me me start by saying I've done all the obvious, all fuses, wires, and replaced o2s. So if my car is heat soaked, on a fire up after sitting my o2s will "freak out" for a couple seconds causing a miss and even sometimes stalling. Once they pick back up the car runs fine. It's given the heater circuit error but I don't think it's consistent. Could it be in the tune by any chance? A small short somewhere not obvious? What wires controls the heater circuit?
02 Camaro H/C/I auto

 

Unless you messed with the tune and changed the voltages etc, then I highly doubt it's in the tune. In my experience changing the switch points to try and correct false lean conditions or correct for long tubes seems to do about jack **** nothing on Gen III's.

Now I will say, you shouldn't be going into closed loop on right on startup. THAT is in the tune, but the heater circuit sounds mechanical, as most codes are typically. If you have access to the tune, you can increase the cold loop enable temps to make sure the O2's are heated up before going into closed loop. You can delay a few other tables too, but this would be the easiest.

Have you checked continuity and voltage on the heater wires? I'm assuming you have. This should be on as soon as you key on, without starting the car.

 

I haven't checked just the heater wires, wasn't sure which ones the are and haven't had a way to do it while hot and it only misses for a few seconds. everything works fine on cold starts it's only on the hot after it's sit for a bit. Which is what's confusing and I thought maybe it's in the tune as I had a real hack do it for me the first time around, and he turned off my o2's. my new tuner doesn't like that I moved wires just to clean things. (Nothing has been cut or spliced just moved). But he seams to be pretty good as everyone else has had luck. Car is in SD so not sure if that changes the closed loop time?

Side note I've recently found your videos on HP and I'm hoping to lean how to use it. Just probably not on this weird issue as I have no idea what I'm doing.