1) I don't know if my IAT sensor even works, I'm assuming I would get a CEL if it didn't, but once I forgot to put the sensor back in it's place (still plugged in the computer) and it drove just like it always did, no rough idle or anything. So could a faulty IAT do this?
Did you ever put it back in place? If not, the computer may be over compensating for the leak in the intake. The computer will throw a CEL if it senses the IAT out of range.
2) How much effect does cold weather have on car's mileage, I know it does, but it seems to have more of an effect this year than last year. And why do cars suffer on fuel mileage when it gets cold outside, maybe a stupid question but I've never really known, just always took it as fact. and by cold I mean -10celcius.
Engines run richer when it's cold out. That helps the engine warm up more quickly. That's also why they use more gas in the winter, as well as the special fuel mixtures used in certain areas to promote "cleaner air."
