I would suggest you replace the O2 sensors pre-cat which is the easy possibility but it sounds more like your Crankcase Vent Valves (CVV) hoses are probably cracked and need replacement. I had some of the same symptoms and it turned out to be my CVV hoses. Just my two and a half cents worth...
V/R Zachary Pullins Sr.
National Capital Chapter BMWCCA
NCC Member Recognition Chairman
NCC High Performance Driving School Back-Up Registrar
NCC Auto-X BOD Liaison
DIY Senior Committee Coordinator
2006 E90 325Xi & 2000 E46 3XXi
" Vision without resources is just hallucination"
Last edited by Zchild; 06-17-2011 at 04:33 PM.
Reason: Additional information