Baron_vM

Hi all... I have noticed that about since winter (dec/jan) up here in New Hampshire I have lost about 2-3 mpg average. There has been no noticeable loss of performance, and I haven't noticed a change in my driving habits at all. Used to get 21-22, now getting 18-20 combined city/highway (~75% highway). A couple weeks ago my CEL came on once indicated MAF issues, and shut off. I cleaned the MAF anyway and haven't seen any real improvement in MPG (did notice performance boost). I threw in a bottle of Techron in my last tank and just filled up a new one today. Hoping that'll help.

Any suggestions on what could cause a loss of MPG like this? I know it's not a lot, but it just seems kinda weird. Thanks.

Fabio D

Yap, the MAF sensor cause this issue, maybe not affect the engine power at this time but they start to get more gas & more gas & more gas & you notice the power loss with the time (maybe 1 week, maybe 1 month or maybe 1 year) this sensors have this problem, at cold start your engine works fine? or you notice some faulty power?

jeff.bisonett

Ethanol in your gas? That'll hurt mpg. I also seem to get less with winter tires

Baron_vM

I avoid ethanol when possible, and fill up only with top tier fuels. I did just get new tires (toyo proxes 4), which may be it because the MPG loss was a sudden drop, not a slow fall. Also, my engine runs just fine at cold start, and power seems to be fine for now. I'll probably replace the MAF in the spring anyways. Seems ok for now though... I'll keep an eye on things. Thanks for the help all.

SleepersRock

i run toyo t1rs in Cali and still get 20-22 mpg at around 75% freeway driving. i did however get much worse mileage when my MAF crapped out. I found that cleaning it doesn't do much. Have a MB shop check it out. There is range (i think its between 1 and 1.1) that the MAF should be running at. Anything outside of that range and the MAF need to be replaced. When I replaced mine it was running at 1.30. As SOON as I changed it the power and MPG came back.

Baron_vM

Thanks for the tip. Think I need to go to the dealer or can my local foreign auto guys to the test do you think? I'll post what i find out.

AMS Performance

Dirt air filters can also hurt. K&Ns will give you a bit more fuel efficiency as well on top of the stock filters. hope that helps

SaMaS

I don't drive my car in winter but I know that few of my friends where complaining about the same thing ... loss in MPG during winter season ...

xlr8tin

I had the same exact tires for winter, and I was in Portland, ME...I used to get 22mpg. I seriously doubt it's the tires...and yes, this was on my E55. I'd look into the MAF.

AMS Performance

Elevation also makes a difference so keep that in mind as well. Higher thinner atmosphere requires less fuel due to much thinner air.

Fabio D

Thats correct!!.. absolutly yes! but the 112's & 113's have the big problem with the maf snsors, change it & you get the normal MPG on your car

Baron_vM

yeah i'll probably end up changing my maf anyways... just passed 72000k which seems like quite a while for one of those troublesome little guys. I wonder if the extreme cold can effect mpgs... it's been a brutal winter up here, and the change in MPG happened around the same time as the change in weather. Thanks again all.