hi there i am an owner of e46 318ci 2003 model i have the following problem.the car idles slightly rough when in neutral gear & once the engine reaches operating temp.while ideling the revs go up & down on there own. is this a crankshaft sensor problem ?
thanx

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW Crankshaft Position Sensor Replacement

Hunting at idle is a common problem associated with an improper mixture. I would read the codes from the car and see if there is a sensor problem, or perhaps a vacuum leak. See this article here: http://www.pelicanparts.com/bmw/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm

- Wayne

If the crank shift postion sensor is bad it wouldn't run at all.

Your car is getting to the age where the plastic parts in the air intake path are starting to crack from age. I replaced the boot that attaches to the throttle body on an '04 the other day because it was starting to crack. These parts are not expensive, even from the dealer, compared to most BMW parts.

You have to dismantle the air intake path to examine these parts. You may want to clean the throttle body and idle air control valve while you have it apart.