In Reply to: Intake Gaskets posted by Anthony on October 15, 1999 at 14:50:41:
Yeah, you've got the test procedure right. Usually the car will stumble if you find a leak though, not rise. I would be slightly concerned about spraying a lot of carb cleaner into your intake as your O2 sensor may not appreciate it much. Maybe some fuel injector spray cleaner would be a better idea since most of those are safe for O2 sensors.
As far as this problem is concered there are about a million FAQs on this on all BMW sites that relate to E30 idle problems. Most of those are about unsteady idles though, not quite what you describe. I would hazzard to guess your O2 sensor may be on the way out, I had the exact same problem in my Jetta (Digifant sucks) and that seemed to be the culprit. Check your intake boot first and go from there. If you check the board archives you'll see this comes up a lot.