2017 Taco gas mileage falling

I have no codes at present. Been researching this. Among the possible issues, the one that seems to find the most comments in other forums is the O2 sensor. Particularly, carbon buildup.

Some claim that cleaning the carbon can restore (though not fully) the O2 (upstream) performance. There are a lot of video's on YouTube but I'm dubious about many of the claims there. Also researched fuel mileage falling on Yahoo. Again the O2 comes up as one possibility. Other possibilities could be dirty or clogged injectors.

I get it. There can be many possible issues going on. The truck is well maintained. Oil changes on schedule, tires rotated and proper pressure. Recently (but fuel mileage falling before this) the truck went in for a fuel pump recall. Was told that this would likely improve mileage. It hasn't. In a few days I'm taking it in for diagnostics. $160.00 for looking at it. Not happy about that. But when pulling out of the garage I have been noticing an unpleasant odor. Not sure if it's gasoline but it stinks. Not badly, but it makes me think of other vehicles on the road that are beaters. Poor condition, probably improper routine maintenance, etc…

Have looked through this forum to see if anyone else has mentioned O2 sensors as being among the possibilities, though I failed to find any. Not saying there aren't any, just being new I'm not good at searches. Your help is appreciated.

 

Does it smell like rotten eggs ?

What sort of mpg decrease are we talking about ?

 

Rotten eggs? Perhaps a little like that.
No check engine light.

Expected:
Summertime highway 23MPG, city 19MPG
Wintertime highway 20MPG, city 18/17MPG

Right now (winter gas formula) 15.9MPG mixed highway and city.

 

You say nothing about your truck other than its fuel mileage.
Perhaps some more specifics - model, trim level, recent changes/mods, your location, etc. might elicit more responses.
Mine is giving me a tank average around 18 mpg. 3.5V6 auto. Exact model is in my signature.

 

Gave a little in my profile.

2017 Taco TRD, V6 (didn't mention before), 4WD, 4 door
No mods yet. May not modify. Might go for supercharger - MIGHT go for.
Without looking, it's around 60K miles.
Northern Utah.
Usually use Maverick gas. Sometimes Tesoro, sometimes other major gasolines (Mobile, Chevron, BP)

 

What I really want to know is if cleaning the O2 sensor is a viable approach or am I looking at BS video's on YouTube?

 

Curious how they suggest cleaning it. Seems like it would be very likely damaged.

 

Exactly why I'm looking for someone who isn't out to score likes on YT.

 

Could be a batch of gas. I always got around 16-16.5 mpg. Now I’m getting 15 mpg with no mods or anything else different.

 

UPDATE: Mileage 28896. Yes, 29K, not 60K. Wife's Venza is 60K. Sorry for confusion. And no, the mileage is not Trip A or Trip B, that's original miles on truck. Averaging 5.8K annual miles. Sometimes I trip across the country for work but mostly I'm just around town. Yeah, that's low mileage, and it shouldn't be having issues so soon.

 

I think the fix might be adjusting expectations. 16 MPG winter is not bad, especially if you have warmups, short trips, even the slightest bit of wind on your highway miles.
4x4 double cab when stock, the best I ever got was 21 alllll highway, no hills or wind, but it usually averaged 19-20 all highway.

 

Generally I'm light footed. Trying to drive the truck at 80 MPH sucks the gas down. Especially against a head wind. One trip I got down to nearly 13 MPG when facing a fierce head wind. I know conditions play a lot. That's why I rarely do more than 70MPH. Truck seems to like 65MPH best. That's where I've seen mileage as high as 24MPG in summer.

 

24 seems really unlikely and may have been a fluke. If you’re getting 16, that sounds just about right to me. If you go to fuelly.com it has 1000s of owners reporting their MPGs. 17 is the overall average

 

If I knew I'd be getting this kind of mileage I might have gotten a Tundra. Chief reason for NOT getting the Tundra was the Highway Safety report that Tundra doesn't do well in front end crashes.

 

Tire pressure is lower in the winter if you haven't adjusted. Plus crappy winter gas

 

respectfully sir; for future purchases, look at the published MPGs and deduct about 10-20%. If that number doesn't fit your overall expectations, look to a different vehicle.
Some have this self imposed idea, that since the Tacoma is a mid-sized truck it should get better MPGs, but it was never designed to be the mid 90s super-light weight, 4 cylinder, 2wd, low rider that got double what a full size did at the time. Instead, it's almost as tall as, wide as, long as a full sized, bloated with all kinds of options and tech (some market driven, some big GOV mandated).

 

Tires are at 38 to 44, depends on where they are today. Winter gas is crappy. Yes, I know these things.

But back to my question: Can an O2 sensor be cleaned and inspire more like new performance?

 

that seems like higher pressure. Most I run is at 35.

Maybe your o2 sensor really is bad and you're running rich

 

Are you stock?

 

Change your air filter if you haven’t lately. I am all stock and getting about 15 mpg all city driving. TPMS is at 35 psi on all 4 tires. My MPG generally drops during cold months and all city driving. I am guessing your MPG will increase once the weather warms up.