MM>You _might_.  Modern engines have anti-knock sensors built into the engine
MM>block to 'listen' for detonation and retard the spark timing accordingly.  I
MM>by using a higher octane fuel the anti-knock sensor fails to 'hear' detonati
MM>then your onboard computer may let the engine run at a higher timing advance
MM>which would improve your mileage.  Even one or two degrees additional timing
MM>advance should give you improved mileage in the range you seek.

 ONLY if there was some problem with the Engine itslef. Like bad timing
 etc.
---
 þ SLMR 2.1a þ This note from El Cajon California USA