Originally Posted by 540DaveMy 95 540i has baffled me with this idle/CEL issue. Some of you are having similar problems but one thing remains different for me..at least I think. Ambient temperature. In the warm weather of a few months ago I had no problems. Smooth idle. Lots of power. Never an issue. Did I mention the power? I used to own a 4cyl Camry.
Now that we have experienced some colder temps up here in Canada, my CEL has started coming on when the car is allowed to idle for more than a few seconds. A warmed up or cold engine seems to make little difference if it was below or near 5 degrees C (40F) when I first started out. The CEL will shut off if you get back on the gas quick enough, but leave the car to it's own devices for too long at idle with the CEL on and it will then stay on even in acceleration. If I allow that to happen the car will then idle rough, and may even stall out. Once the rough idle starts and the CEL is on I am stuck with this situation until I shut the car off for a while. Then I start from scratch with normal idle and no CEL. But it comes back. It seems worse with in town driving but that may be because it never gets a chance to idle on the highway but even then, if I am completely off the gas for a bit on the highway (long downhill or off the gas after hard acceleration) the light flashes on and then goes off when I hit the gas again. The kicker is that sometimes you get smooth idle and no problems. Sometimes after a run in town it will just stall dead as soon as you come to a stop. It varies. It runs great on the highway and has lots of power but only idles smooth with no CEL intermittently or for short periods. Is it the ICV? Is it a vacuum leak? Should I wait until spring and sell the car? I don't want to spend hours of labour on diagnostics at the stealer if you guys know what this is. Please tell me!
I don't understand what's different from this situation and the other current and old threads on this beaten-to-death topic?
best, whit