Hey all. Long time no see!

I got a question thats been plaguing me for a while.

I know that the higher gasoline octane rating the more the fuel burns v.s. exploding in the cylinders making it knock resistant. And higher octane fuel does not supply more oxygen.

But does higher octane gasoline require more oxygen to burn? Currently Im living up in the mountains of Arizona for school and comming from sea level to 5300 feet, I can feel my truck is down on power. 06' Nissan Titan (9.8:1 compression, all aluminum) One day I treated her to mid-grade and after some driving around I noticed the ECU worked its magic and she seems happier.

Is my truck really happier or have my engineering classes made me insane?
I do notice going down to Pheonix my truck has her power back due to the increased oxygen at that altitude.

-CJP