Volvo Repair: 84 240T wagon idle problems, turbo wagon, speed motor

Question
Recently purchased 84 240 turbo wagon, AT,  for son learning to drive.  176K miles.    When purchased last month, intermittent miss at idle.  Now it won't idle and stalls at stops unless manually maintaining idle speed with throttle.  Good spark, fuel pressure within posted specs, clean throttle body.  Will occasionally (though not consistently) idle at ~1300 rpm after driving and placed in park. Runs great otherwise. Thx for your help, ---rick

Answer
could be many things.I would try disconnecting the airmass meter and see if it idles then if it does it is more than likely bad.the airmass meter is located in the hose that comes from the air cleaner housing.it could be the constant idle speed motor is bad.this is located under the intake manifold.when it idles at 1300 try hitting this motor with a screwdriver or tap it with a hammer and see if the idle drops if it does then it is more than likely bad.