My parents own a 2003 X5 4.4i Sport with 51k…the car is in immaculate condition, and is driven mostly on weekends on highway…oil is changed every 3k and maintained to the highest extent…

Recently the Service Engine Soon light came on…when I plugged it into my code reader it came up with a code that read "Mixture Control, Idle, cylinders 5-8"

The car runs just fine and drives the same, but we are holding from driving it before we find out what it actually is…

Anybody know what this mean?

Thanks!!