for about 3 years my 4runner got near 17 mpg in city with the 2006 V6 auto. This was confirmed by both onboard computer and mathematically checking it. The last and I am going to guess at this, 18 months I am getting 10MPG. I haven't changed anything to speak of. Had new plugs and filters put in to try and help but it did not. Breaks are not dragging and tires are at the top of their pressure range. Any ideas what I could do or could have done. to cause this or to fix it. Thanks
GAs Milage Dropped from 16 to 10
- Thread starter Dunk50
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How many total miles on the clock? Should try cleaning the MAF sensor. Also may not hurt to replace the o2's as well.
CNJ Runner
New member
I have n 06 sr5 v6, the same thing happened to me for about 1-2 months then my cats went bad.. but 10 months is a while before your dash lits up like a christmas tree
It has 36k miles, never touched the maf sensor or o2's. Should I just have them replaced or what? Did not know they could clean a maf. Also anyway to check a cat. I was thinking of putting on an aftermarket exhaust anyway but was thinking more of a cat back, would have to go all the way to the header if that is possible. I plan on keeping it soee I am open to suggestions.
cali_axela
New member
You can buy a can of special MAF cleaner at most chain auto stores, CRC i believe is a common brand there -- it's simple and cheap. Easy to get to the sensor, just have to spray carefully and let it dry out of the car for a little while, then put back in and good to go. I clean mine every 30k or so, definitely doesn't hurt, chance it can help. I wouldn't pay a shop to do something so simple though, just do it yourself if you wanna see if it helps first 
For me personally, terrain makes a bigger difference in gas mileage than any minor maintenance issues, has that changed at all, or same driving as usual? For instance, I live in a fairly hilly part of San Francisco, and my daily commute each way is almost as many vertical miles as horizontal, haha. So I get horrible mileage on that type of driving. But when driving out of the city, I get way way better mileage without the city stop-and-go on hills killing the mpg.
For me personally, terrain makes a bigger difference in gas mileage than any minor maintenance issues, has that changed at all, or same driving as usual? For instance, I live in a fairly hilly part of San Francisco, and my daily commute each way is almost as many vertical miles as horizontal, haha. So I get horrible mileage on that type of driving. But when driving out of the city, I get way way better mileage without the city stop-and-go on hills killing the mpg.
Nuke
New member
A confirmed loss of 6 MPG is significant. Since you've verified it's not the brakes, then it's certainly something mechanical and the first thing that comes to my mind is either an exhaust blockage (cats or muffler) or significant tranny or other driveline binding. If was driveline, I'd think it would have failed by now.
Regardless, a 6 MPG drop is also noticeable as a major power loss. Was this gradual or sudden? How does the car feel otherwise?
Regardless, a 6 MPG drop is also noticeable as a major power loss. Was this gradual or sudden? How does the car feel otherwise?
Well, I would say it was a gradual thing as I never noticed anything until I actually started checking the mileage that was displayed on the dash computer. Vehicle runs good, no terrain change, power is good and tranny seems to be working fine. All I can say is that I can't tell any change except for the mileage. Could / would the exhaust do this if the cat was partially plugged. I ask because I don't drive it very hard and I am thinking that at low speed and rpm's it could run ok but maybe it will stumble at higher rpm's. I will check that when the wife brings it home. I also am not so certain on the brakes! I was driving along about 50mph and let completely off the gas. It would not coast very far and really seems to drag somewhere. Don't know if that is for real or just my groping for answers. How about putting synthetics in transfer case and axles??
Nuke
New member
If the change was truly that dramatic, it isn't a fluid issue (unless something is dry in which case I'd expect a failure of that component).
In your latest post you mention now that you believe there's evidence of brake drag or some other resistance to rolling. That definitely sounds like the issue. Just find the culprit.
In your latest post you mention now that you believe there's evidence of brake drag or some other resistance to rolling. That definitely sounds like the issue. Just find the culprit.
Nuke, again thanks but it's just a seat of the pants feeling that when I let off the gas it slows down a little to fast. Problem is I would think that this has been going on for over a year any dragging brake would have failed or heated up enough to smell or they would have found it at last service where I specifically asked them to check brakes. I will investigate it further. Thanks again!
KB084RUNNER
New member
First clean your MAF and if you have a Hydrocarbon filter get rid of it. Then pull the EFI fuse for 20 minutes and let it reprogram itself.
"Hydrocarbon filter" ?????? Where and what is that.
