knock sensor?
 

On my 1993 325is, my fault code reads that my knock sensor is bad for cyl 4-6. I have not experienced any detonation, but am planning to replace it soon. It's tucked under the intake manifold on the block itself. Has anyone changed one out? And how much work is involved -- as removinng the manifold for that little thing annoys me.

I dont know what is involved in actaully getting access to the sensor. I imagine you do have to remove the intake manifold, however removing the sensor itself is easy. Just unbolt it from the block.