Moved to Texas from Colorado and now my engine knocks especially with the A/C on which is most of th time here in the summer. I ran in colorado on lowest octane. Suggestions helpful.

 

Difference in elevation, Try Resetting the computer.

 

Good thinking.

 

Also if that doesn't work for you try a higher octane. At a lower elevation you get more air into the engine which makes higher compression and if you were on the verge of knocking up in CO it would be easy to see why you are knocking down in TX