Volvo: 1994 Volvo 850 idle, volvo 850 wagon, volvo enthusiasts

Question
1994 Volvo 850 wagon - std fuel injected engine - manual shift. Normal idle is about 850 RPM.  Usually pretty steady - hot or cold engine. When coming to a stop, I usually depress clutch and downshift, keeping clutch depressed.  BUT LATELY, randomly, idle keeps dropping when i come to a stop, past normal 850 RPM, sometimes recovers, sometimes goes to zero (i.e. car stalls).  Never a problem restarting (and if I let clutch out before stall, engine RPM recovers) and all is fine again.  Power normal, shifts normal, etc.  Any ideas?  Is there an idle stabilizer/injector of sorts that could be faulty/intermittent? I have used 3 cans of injector cleaner in gasoline - no change.  Thanks for any advice.

(And, oh by the way, car engine whistles when cold in winter (say, below 40 degrees F) until it warms up.  The kind of sound I guess that air would make passing over a small opening like a flute... but higher pitch... varies with speed of car (faster = higher pitch)).  Does this suggest a problem with air intake?  Has been doing this for 12 years!!! Dealer stumped and we've given up on that one.


Answer
it's possible that you have an  EGR system and  on your car (exhaust gas recirculation). A stuck open egr valve causes stalling when coming to a stop. IF you have this system (the exhaust manifold has some connections on it) and it leads back to an EGR valve and then goes to the intake manifold, my 87 volvo doesn't have one, so i don't know what the volvo ones look like. i'm not sure what else it could be because there are so many causes for these types of problems, do you have cruise control, if yes check vacuum hoses and switch at brake pedal. for that matter check all hoses under hood. check out www.brickboard.com, there are highly skilled volvo enthusiasts on that site.