I have a 2007 pacifica 4.0. Lately on cold mornings when I try to shift to reverse or drive the engine shudders and stalls. It will do this a couple times unless I let it warm up for 30 minutes sometimes longer on sub zero days. It starts just fine, idles just fine until I try to shift, and only occurs on cold mornings. I originally thought it was the IAC valve, but I cannot seem to find it and the only thing resembling the iac valve looks like it's built in to the throttle body casing. I'm going to remove the throttle body and clean it thoroughly. Iv scoured the internet for information but have come up with nothing. Any help would be extremely appreciated. I'm kind of dumbfounded.