Hello. I am having a problem with wife's '93 945 (non-turbo, 8 valve, Bosch ignition, 190K miles). When it gets cold and the fuel is 1/4 of the tank or less the idle is pretty rough and sometimes even stalls and is very hard to start. After a few seconds of idling everything is fine and the car drives perfectly. I tried to clean the air valve (the thing under the intake manifold feeding the air from the air cleaner past the throttle plate). Not sure if I did a good job. How to make sure? Anyway, I am just wondering if the problem may be somewhere else. When it is not so cold, but cool, the car stumbles very slightly upon cold start and again, after a few seconds is ready to drive and runs fine. So, the symptom is there all the time, only it gets much worse when it is real cold and somehow the fuel level seems to have an effect, though I still have not proven that beyond any doubt. Any ideas out there?

Many thanks in advance!

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Vladimir. '98 S70 base, 5-speed manual - his, '93 945 (approaching 200K miles and rolling on...) - hers