MPG drops in cold weather

[kbeeson]

It appears my MPG drops when it turns colder out. my usual 19-20 in the summer goes down to 15-17 in cold weather. This is on a 99 v6 4runner. I've put new plugs, changed oxygen sensor of late. Are others seeing this behavior? Is there a fix?

I don't spend a lot of time idling vs the summer, maybe a little more.

 

[Qyota]

A quick search would have told you the answer. But yes, this is common. There are several factors that play into it. Less energy per gallon of fuel ("winter blend" has more alcohol or ethanol), longer time in open loop (richer fuel mixture until operating temp is reached), longer idle times, cold moving/rotating parts take more energy to move, etc., etc.

 

[kbeeson]

It appears my MPG drops when it turns colder out. my usual 19-20 in the summer goes down to 15-17 in cold weather. This is on a 99 v6 4runner. I've put new plugs, changed oxygen sensor of late. Are others seeing this behavior? Is there a fix?

I don't spend a lot of time idling vs the summer, maybe a little more.

Thanks for the quick response. I searched more and appears to be normal. Now I got all excited reading about cleaning the throttle body and doing the TB O mod...this forum is very cool. thx. thread closed.

 

[blue4r]

Plus, cold air is denser than warm air hence the MAF compensates by directing ECU to use more fuel to balance out the mixture.....