Code 91
 

What can cause this code if you have already changed both oxygen sensors and you know the car is not running lean? Has anyone ever had this code before and what did you do to fix it?

Thanks

If you're getting a code 91 and you've replaced both oxygen sensors, then there's something else wrong, is this a mass air car or a speed density car?

Mass Air Car...and ive checked and checked again and I cant find any vacuum leaks either...