I get about 450-470mm Hg when cold and 500mm Hg when warm. Not a huge difference, but yeah, some difference.
The cold start injector switch is most likely the cause, and hopefully it's just that since it'd only be a minor annoyance. But I will need to have the rest checked out anyway.

Those vac measurements are spot on.  The higher idle on cold is usually why it drops.  Yours are much better than mine!  On cold start mine are down around 300.
 
Ugh more to check..

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I thought I would post a quick update: I haven't had any problems with cold start stalls for a few weeks now. I have used a fuel injector cleaner in the gas tank (Chevron) and done a coolant flush and refill. I doubt the coolant flush would have anything to do with it, but I thought I would mention it just in case.
I hope this can help others having a similar issue.

So the injectors were not 100% clean. I would suggest you change your fuel filter immediatly and run some nice fuel cleaner and premium fuel . This probably also explains why your having bad fuel economy
Cheers

Thanks, yeah I did replace the fuel filter around the same time I used the fuel cleaner and I have only been running 98 fuel since.
I will probably run some more fuel cleaner soon and I might change the fuel filter again before the end of the year.