im not running iacv and i live in nova scotia today its -4 and started no problem. are you using the air assist? that's all i have hooked up. i idle at 750. around 1200 on a cold start. before i hooked it up i was getting the code for o2 sensor not heating up quick enough after 60 seconds. like you said in the warmer weather i wasn't getting the code, it got cold, got the code, so i hooked that up and no more codes.