1995 E320, 90,000 miles, engine wiring harness replaced.

Cruise control completely inop. idle to low--about 500 rpm--occasionally dies when power steering loaded or ac cycled on.

CEL on, code 6 (Idle speed control faulty) Can clear but will come back within a day or so.
PIN 8 code 8 (Idle speed control at upper or lower control stop--limp mode does not appear to be active)
PIN 14 code 2 (2 EA/CC/ISC control module (N4/1) or Safety contact switch (M16/1s1) or Stop lamp switch or Cruise control switch or Actual value potentiometer or Starter lock-out/back-up lamp switch or engine speed signal or vehicle speed signal or closed throttle position switch or safety relay in EA/CC/ISC control module)

PIN 6 code 3, 4, 8 (don't have look up table for these)

checked stop lamp switch above brake pedal--appears OK

Dealer says: HFM SFI diagnosis: possible cause intake air leak or throttle valve binding

Is this the dreaded throttle actuator problem?