I have an '89 244 like yours. I had a bad 02 sensor last year and it gave me a bunch of symptoms, but it was only slightly rough running and then only when the engine was all the way heated up. Gas milage was bad an plugs were getting fouled because it was running very rich. I had a big problem getting the old sensor out, so I wound up unplugging the sensor and found that it ran much better in the meantime that way.

Is your check engine light on? Have you checked for codes in your On Board Diagnostics box under the hood? If you don't have any codes, I wouldn't think it's a sensor.

Besides vacuum leaks, I would think you would want to clean your throttle body if you haven't done so lately, or never have. That would give you a chance to check most of the vacuum hoses, make sure all the vacuum ports are clear, etc.
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Andy in St. Paul, '91 745 Regina 198K mi, '89 244 142K, '87 245 RIP