How did I get 15.5 MPG?

[Jeff Jackson]

2006 Lux H2

Dealer told me removing the roof racks would improve mileage 1 mpg
Did not remove because I like the look

Replacing the exhaust system and air intake system would improve mileage 3-4 mpg
Had that done. More power but mpg remains the same.

Put in BP 89 octane instead of 87 octane
Noticed a marked improvement in performance and mpg

Read this forum and today I put in Sunoco 94 octane
No change in performance but gas mileage actually DECREASED!!!

I'll try one more tank of higher octane and post the results.