Ok here's the scenario... I live in canada, Got gas at two different shells, one in toronto, the other in Brampton. My gas milege has changed drastically. Anyone can explain this?? I have no engine mods also.

 

You drove differently. The fuels were of different blends. You drove differently. The octane was lower in one and higher in the other. You drove differently.

It is very possible that you just drove differently.

 

I think it's due to different driving. Or driving differently.

 

as the kind gentlemen above me have stated,

there's just so many variables, and that maybe you drove differently.