960 surging and no power plus more

[Bfranklin]

Good day all, this will be a fairly long one. I have a 92 960 wagon with 176000 km on the dial.
Symptoms
On occassion (once or more per day) when the car is started and you attempt to drive the engine surges, the tach goes up to 2500 and down to about 1000, up and down. If you place the car in neutral its the same. If you turn the car off and resart the problem is usually fixed, and the car seems fine.

Often while driving the car, and when attempting to accelerate the engine looses power at 3200 rpm or higher, but does not stall. You can drive as long as you give very little gas. However on occassion it starts to surge when acclerating even a little just like it does on startup as previously mentioned.

Yesterday i got code 212 which is 02 sensor, its about a month old.

Lastly i am unsure if this is related but the vacuum at the heater is acting up, when its in the floor position, the majority of heat comes out of defrost when accelerating i can hear it move to the floor vents ???

A good used map has been installed, o2 sensor, etc, no one can seem to correct this problem, any help or suggestions would be appreciated

Bruce