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Warm doesn't always mean closed loop. On the newer obd2 cars its easier to figure out with a scan tool if it is or not, though some fault codes on them that turn on the cel will take it out of and keep it in open loop. I would think if the O2s were fluctuating then it would be in closed loop. I guess another way to know is if the timing is fixed and not advancing or retarding. And that is your next assignment, use a timing light and see if the timing is changing when it does the surging.

Yes plz drive the car more if possible. Try to get it on the highway to push the rpms some but pay close attention and be careful. 950 rpms is too high when in drive with your foot on the brake. This tells me that the computer is compensating for some type of lean condition. The car has to be driven a certain amount of time for it to generate a code.