My 1994 325i has started surging horribly when I start the car. It revs up and down while in park and neutral. The rpms go from 1000-2000, then 1500-2500. It used to not do it while in drive but is now surging in drive also. The check engine light went on - found code 1221 - replaced the o2 sensor with Bosch, using the realoem.com website to find the correct part number and ordering it from pelican parts. That did not help the surging.
Any ideas before I take it to a BMW mechanic?

you might want to try the e36 section

sorry - can this post be deleted? thanks.