I just thought I'd put my two cents in here.....I live in Alaska, both my bricks live outside year round (I know, I know, I really should clean out the garage) Besides difficulty turning over after sitting for more than a week, I have never had a part fail due to outside air temp (Don't forget, they're made in Sweden) If you're really concerned about the air temp affecting your thin-blooded bricks, try picking up a portable ceramic heater ($50 at most hardware stores) and run an extension cord out to the car; park it under the engine and leave it on medium for the night, it will keep things warm. Good luck with the weather, nice and warm here today....Kevin

(I'm pretty sure it's your IAC motor, it is a pretty quick fix)



'93 945 165k; '97 850 T5

Is your foot on the brake pedal when this happens? If so, does it stop if you put it in neutral and take your foot off the brake?

If the answer is "yes" to these questions, then it's likely the vacuum check valve on your power brake booster.

The part is very simple to replace (should take 5 minutes, tops) and only costs about $10-$15. A word of caution: replace it after you’ve driven the car a while. Because it’s held in by a rubber grommet, and the rubber needs to soften with heat during the winter. When I changed mine last winter, the plastic part broke while still in the booster. It was a real pain getting the remainder out.

Good luck,

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece)

I got the same symptom when I unplugged my idle air control motor (actually when I inadvertently didn't plug it back in after cleaning it) - a wavy up and down idle from below 500 up to as high as 2000. The extreme cold makes a lot of things function terribly. I went to refill my windshield washer res yesterday and the lid was so cold it just broke in three (normally a flexible piece of blue plastic).
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Darius in Albany NY '86 744 GLE (174K); '91 745 Turbo (164K)

Do you really use an 11 year old battery??? No offense, but I think in the cold weather you're suffering through, it's just plain crazy not to replace it. That guy has been living on borrowed time for years.

The FAQ have a section on idling problems. If this only happens in very cold weather, it must be something which changes when cold. Things which come to mind are: sticking IAC, sticking TPS, vacuum leaks caused by shrinking metal parts thus opening gasket seals such as the intake manifold, vacuum leaks in the air hose from the AMM to the throttle body.

Sounds like a sticking IAC. If it warms up a tiny bit you may want to consider just braving the cold yanking the IAC out and bringing it in your house to clean up. It's basically 2 hose clamps and that's it. I don't recall there being any bolts or nuts to loosen, other than loosening the hose clamps with a flathead screwdriver.

If it were your AMM, I would think that your problems would show up everywhere (not just during idle and warming up).
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Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

I'm fighting something similar on my 93 240 right now except the loping up and down only occurs if I try to go. It will idle fine cold and after it thoroughly warms up it runs perfect. I've done alot (following suggestions from this forumn and the faq) and my next try will be to replace the ECT sensor tomorrow and a new intake gasket as it's easier to get to with the intake manifold off.