when replacing all oxygen sensors how many miles do i have to drive as to get an emissions test done?
Only two oxygen sensors need to be replaced not all 4, 2 measure air flow and 2 monitor the cats, the ones that go bad are ones that monitor the cats. You'll be good for emissions right away. They're easy to do yourself many diy's out there, check bimmerforums. For the sensors www.oembimmerparts.com
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