1991 BMW M5 6 cyl Two Wheel Drive Manual 181000 miles
Hello. After I drive my car for a long trip (80+ miles), the check engine light will come on with a code of 1221 (oxygen sensor) when the car is at idle, such as at a stop light. Once I start moving again, the check engine light goes away. I have a new water temp sensor, oxygen sensor, MAF and vacuum hoses. Why is this happening only at idle after long trips? Does not happen in city driving.