2001 Spyder Cold Idle
 

I just purchased a 2001 Spyder. I have only had the car for a week, 100 miles. No real issues other than a weak heater, she's 18 years old so I'm ok with some squeaks and vibrations while I fix her up. My major issue is a very rough idle while in gear and the engine is cold. I normally warm up for a few minutes, but on my lunch break I don't have time. When I get to a stoplight I have to put it in neutral to alleviate the vibrations. It does not try to stall or lose power, and once the engine is at temperature it runs perfectly. Acceleration is good. I bought the car in an emergency situation and have to save up to get to a mechanic, so I'm trying to pinpoint little issues that I may be able to fix on my own in between. At this point I am leaning toward a vacuum leak or busted motor mount, but would really love any input from those with more experience with this car. Thanks a bunch!

Edit: She has 120k total miles