Mine did. 91+ your truck has the ability to run more timing which means more power and less fuel.

 

Well if running 91 leaves more carbon deposits, would it be a good idea to use one of the many fuel additives that claim to reduce or even remove carbon deposits. I think STP makes a product that claims to clean carbon deposits.

 

Do a little reading before you go and dump hundreds of dollars more a year in gas.

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

http://www.exxon.com/USA-English/GFM...y_gas_faq.aspx

http://www.bargaineering.com/articles/high-octane-gas-myth.html