Das Boots
04-05-2004, 05:29 PM
Recently replaced O2 sensor. All was fine. Gas prices went up. So I used midrange octane. The used the premium octane again. Since then, Check Engine indication on and off. With no specific time or speed. Checked the plug and all is ok. Do I have a bad O2 sensor by using midrange octane? Tested using Peake tester and O2 sensor shows. Need all the help. By the way, this is for a '92 525i. M50 engine. Thanks.