Could be any or all of the above. My problem was deteriorating wiring insulation within the ETA and MAF harnesses. Once I fixed this, my surging was gone.

http://www.v12uberalles.com/MAF_rewire.htm
http://www.v12uberalles.com/throttle_actuator_rewire.htm

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1995 S600, 1 of 618 (sold)

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