I drove a 2006 ss s/c from California to Kentucky and my check engine light came on with a lean air fuel mixture. Could it be the elevation. The only thing that is mind boggling is the Computer should change preferences to were i am driving. I dont know i checked for an intake leak, nothing. Nothing found at all! Any body have any awnsers?

Thanks

 

Could be your intake if you have one. I have one right now as well (CEL)

 

If you have an intake and know someone with HP Tuners, they can take care of the check engine light. It happened to me.

 

cold weather does it too....i noticed my trims are going +1 when they are usually -3

 

If you were increasing in elevation the car would actually be richer. Not leaner.