07 CTS-V lean code
It does affect when it knocks, but not the A/F ratio.
Did you look up the code itself, or is that what the owner is telling you?
Put the code here in case you need help looking it up, though Google is pretty good at that.
It might be a knock code from running on regular when 91 or 92 would be better for it.
Bottom line, get the actual code and look it up. Then you know.





