Poor MPG in winter?? - Toyota Nation Forum : Toyota Car and Truck Forums

tyler2569 · 10-23-2009, 02:58 PM

Hello, switching my stock filter out for a TRD filter in summer proved to be a great benifit in MPG... Summer MPG combined City and highway = 42 .... however as soon as cold weather comes the MPG drops like a sack of weights.. Combined City and Highway = 32

I switched my TRD filter to the stock filter for winter, and so far my MPG went right back up.. Weird??? i dont understand?? Why??

I know tire pressure effects mpg, and in winter tire pressure drops.. but it shouldnt cause a 10mpg drop..

I run royal purple oil 5w-30.. with mobile 1 filter.. nothin else changes except for the the outside air temp..

2008 yaris 1.5L 5 speed sdn

***humanoid*** · 10-23-2009, 05:28 PM

Winter blend gas may have something to do with the MPG drop. Changing out the filter back to stock will also cause your ECU to relearn the fuel to air mixture. Give it a few more tankfuls for your EDU to relearn and report back on the MPG.

Stevo_Echohb05 · 10-26-2009, 01:10 PM

Plus you idle high until it warms up

jambo101 · 10-26-2009, 03:20 PM

I always get 25% poorer fuel economy during the winter,probably has to do with winter formulated gas and the car running cooler a lot more often.Whatever it is it seems to be normal for all cars.

denman · 10-28-2009, 11:11 AM

Ditto the above, but have you tried an hour or two of block heater before cold starts? My car runs OK off a cold start, but my MPG really hurt for the first while. How do I know that you may well ask?? My new ScanGauge II tells me so. OOOH I do like that thing!

Yaris Hilton · 11-12-2009, 10:03 AM

Many people run their car to warm it up before getting in and driving off. Not only is that harder on the engine than driving it to warm up, but it's consuming gasoline pretty fast at exactly zero MPG.