One more engine problem to diagnose:
Just a week ago, the car started idling very horribly at startup and only holding about 400RPM, on extremely cold days it dies out. If I hold the accelerator at 1500 RPM for about 3 minutes, it warms up enough to idle properly, if a bit rough. After it fully warms up, the idle is fine and everything seems to work great.

Replaced the IAC solenoid about 2 years ago to fix a similar issue. Gave the TB a good cleaning and it worked great afterwards. I guess I could have got a bad IAC that just failed early, but I want to know if there's anything else to check. Originally I had to do the repair quickly, so I used a Duralast part that was a direct fit. I would have preferred OEM but nobody local had them.

Anything else I should check or just see if Autozone will swap out the IAC they gave me?
Thanks.

 

Sounds like an IAC to me. I'd see what the warranty on that part is.