Re: more on '87 TQW idle problem?

[glen.powell@smc.com]

  OK, additional debug info. I removed the idle stabilizer and
  plugged the two hoses. The engine will now die if the revs
  are not maintained with the throttle, however, the revs can
  be held stady at any RPM, right down to 800 + 900 RPM,
  this is impossible with the idle stabilizer installed. Oh, by
  "removed" above I mean physically removed and the
  two hoses plugged, NOT electrically disconnected.
  When the stabilizer is electrically disconnected, there is
  no difference in failure mode, idle still surges from 1100
  RPM up to 1400 RPM, then drops instantly back to 1100
  and repeats at about a 3-second frequency. I cleaned the
  stabilizer, still no help. In looking at the stabilizer, I can see
  that the CPU is varying the airflow by modulating the valve,
  it all looks OK, but when reinstalled the problem is back.
  Is it a common failure mode for these stabilizers to leak?
  I wonder if a poor seal inside is causing a leak that results
  in the high/increasing idle.....These suckers are like
  $125 US, so I'm going to look at the O2 sensor voltage
  before blindly swapping this puppy out. Any other ideas?

  -glen