2 + MPG drop after switch to M1 0-30

[SilverC6]

My Toyota Sienna picked up 1 mpg when I switched from fuel saving dino Pennz 5W-30 to M1 0W-30.

I'm making money buying the more expensive M1!

I'm thinking about converting the rest of my fleet, except for my son's RX-8, to this magic money saving oil.

 

[hooligan24]

would a 2001 set a check engine light for a faulty gas cap? I have read somewhere that faulty gas caps is a big problem with fuel evaporation and a possible cause for bad mileage. it was a quite substantual amount of fuel lost world wide.

 

[Jason2007]

yes, because it is part of obd 2

 

[mpersell]

Winter fuel is blended to be more volatile. A good running ECM will detect in the O2 sensor and dial the timing back a little bit until it gets really cold outside.

Originally Posted By: wavinwayne
What is it about winter gas that causes MPG drops?