I always look forward to the cooler months, primarily because my truck runs like a scalded dog. [Did I just say that? Nevermind, it's slow, way slooooow.]

Anyhow, I could hardly contain my excitement when the outside temperature gauge read -8 (F) last week. It seemed forever to get warmed up, but after about 30 minutes of driving it was time. I dropped the hammer.

The poor truck bogged as if it was running with a plastic bag over the air filter. I tried again. Same thing. So what happened? I don't have an AF meter, so perhaps I went way lean/rich? May I was blowing the spark out? [I don't even want to tell you what the boost gauge read.] I'll add that this doesn't occur when it's 20 or so.

 

It's really hard to say without data-logging to see what is going on. A wideband O2 would also help in this situation.
More fuel is needed when the air is cooler. However, a properly calibrated air meter, and a good tune, will compensate for the changes in air temperature/density. I know my truck runs great in these cooler temps and its common for me to see 15+psi during this time of year.

 

It was the plugs. Dropped in a new set of Denso's and the symptom no longer occurs. Not that I could notice any noticable 'wear' in the ones that came out...

 

Thats good news.
Mine loves cold air. I always say "There's horsepower in the air" on cold days. But -8... whooo thats cold. Glad I'm down here in the sunny south.