Crankshaft Sensor only works when heated with heat gun

A friend of mine has a 95 318i. When the temperature drops the car will start and idle fine but when he revs the engine it will hit a 1000rpm and seem like the rev limiter kicks in. As the engine warms the rpm's increases along with the engine temperature. If he heats the crankshaft position sensor with a heat gun with the rest of the engine cold it will rev fine. He replaced the sensor but it didn't change anything. Any ideas?

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

[Wayne 962]

This is an odd problem. The only thing I can think of is that the wire harness is a bit old and there is resistance in the harness that changes as the engine heats up. I would check the resistance between the DME and the sensor. Also make sure that the crankshaft sensor is firmly mounted, and also the sensor pickup points that the sensor reads are clean and clear of debris.

- Wayne