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Well an upload of it in progress would be great but if it's like what you mentioned, it's most likely the IAC stepper motor being all wonky like someone else mentioned. When I verified base idle on my truck by grounding out the ALDL pins and such I could hear a bunch of noise from under the hood until I disconnected it per procedure. So, you could just try unplugging your IAC and then starting your truck to see if anything changes.
If it's a parts store brand EGR (anything other than AC Delco), check it to make sure it functions as it should. The parts store junk can be hit or miss. If you depress the plunger on the EGR at idle, the truck should stumble if it is working correctly.Got the new EGR in, idles much better, tho still stumbles a bit on occasion, but I'm pretty sure it did that before the really bad idle.
This stumble is almost like a miss, but very random and sporadic.
I'll see how it handles traffic tomorrow and report back.