Lower MPG

So recently I’ve been getting about 14 mpg and a while ago it was about 16-17. Any ideas? I don’t really step on it.

 

me too, I have a 2nd gen 2.7l auto all stock, I cannot get over 19.5 mpg this Winter I was hoping to get over 20 mpg even with winterblend gas, new plugs, airfilter, proper tire PSI

 

Check your vacuum hoses
Do the propane pass over test

 

Don’t see why your complaining 19.5 is way better than 14.5.

 

if you check the mpg threads on this site from back in like 2012, we were all getting better mpg. of course the vehicles where not so old then, but Ive been trying to determine the objective reason besides just the "old truck" comments.

ive had my truck since new and i used to get minimum 18mpg town and up to 24mpg highway. now i get as low as 11 mpg town and 19 highway but usually about 14 or 15 mixed. i have a v6 4x4 fyi. i also get better mpg in certain states. Arizona and New Mexico i got better mileage than California and Texas. Texas gas was real bad. like 15.5 highway. but it was half the cost of Cali gas.

ethanol gas is part of the reason i believe for the poor mpg these days. despite the government's propaganda that ethanol doesn't hurt mpg.
besides that i believe dirty or leaking injectors might be one of the bigger factors. another theory is worn piston rings and valves that need adjustment.

other factors that cause poor mpg that some of us on this forum have addressed is a clogged catalytic converter, very old o2 sensors, dragging brakes, etc...

first step is a tuneup with new spark plugs and wires, air filter and replace old vacuum lines. then make sure your tires are stock street tires( if you care about getting stock mpg figures). after that start looking into the things i mentioned

 

Any chance you are getting e15 (15% ethanol) in your state? I think the government just approved its use last year from the old e10

 

You're looking at a 2% or less difference for e15 fuels compared to "normal" fuel.

https://ethanolrfa.org/2012/07/use-of-e15-in-your-automobile/

OP has a ~15% reduction. His issue is more than likely MAF, IAC valve, and any of the other regular maintenance items discussed in the numerous MPG threads.

Also, e15 has been around since ~2001

 

that's the BS govt statements I'm referring to. i don't believe it. but even according to their statement, e15 has 2% less energy density than e10. my truck at least wasnt designed to work with e10 despite being made in 2001. being able to use it and designed to use it are two very different things. i don't want to hijack this thread into a debate on ethanol. and my seat of the pants gut feeling isn't authoritative, but i still think it contributes to generally lower mpg than when our trucks were made.

 

If you don't believe a long standing published statistic based on nothing but your seat of the pants feeling and a general distrust of the government, then there's nothing I can add.

Double or even triple the loss in MPGs from e15, and that's not nearly enough to account for the OPs drop anyway.

 

true, but I got the truck to use as a daily driver and figured on getting 20mpgs or more no matter what the season or situation, my old 2004 with a 3.4l v6 i could bank on getting 20.5mpgs like clock work

 

way to get that upper hand. you win the internet today bud.

btw i didn't attribute any particular amount to OPs mpg. i just think it's probably more than the stated theoretical difference of 5% of E15 to pure gas. probably due to the fact that our 1st gens weren't designed to use gas with ethanol. i don't doubt that modern cars properly designed for it can run it with no problem. less compression especially as the truck gets older probably leads to less complete combustion exacerbated by the ethanol which i believe requires higher compression to burn completely. we're taking a bigger hit to mpg than theoretical idealized published govt data which is based on modern cars.

 

Well I’ve seen older 4Runners getting 16-19

 

How long ago were you getting 16-17mpgs?

Was it a gradual decline or was it drastic...like from one tank to the next?

Any changes to your truck in that time?

Do you track your mpgs in a sorta verifiable reliable way? For example I use fuelly but because I have 2 fuel tanks and my filling pattern is variable plus unaccounted for tire size makes fuelly unreliable. On the other hand my motorcycle and car are tracked with consistantancy and are probably about dead on accurate.

 

We have a 96 Taco about ready to roll 300k. My teenager drives it and the MPG has tanked recently. He is replacing the O2 sensors now.
He doesn't have the CC in it anymore, new clutch recently, aggressive street tires on it.
What MPG are you guys getting on the higher mileage tacomas?

 

I know exactly why his MPGs went down, lol, it's not the o2 censor, lol.

The car I drove in highschool was getting some outside wear on the front tires. so my dad and I went in for an alignment. Tech said the alignment was perfect and I just needed to slow down on the corners...

BUSTED!

People typically get anywhere from 15 to 19, all depends on tires, 4x4, v6, but mostly just how you drive. Some claim they get 25 in their 4x4s, lol...

A clean MAF and a few other regular maintenance items can't hurt, the the #1 factor is that right foot.

 

"Long standing published statistics" (from the Government)?

Aren't these the same people who regulate the bullshit MPG numbers posted on the windows of new cars? Does anyone actually believe those numbers?


He has a point about the ethanol... our trucks weren't designed to run ethanol (at all) we see a drop in milage at e10... the difference between e10 and e15 would not be straight across... it would be compounded.

IE the milage decrease would not be a straight line on a graph... meaning it would not be say 5% drop from e0 to e5 and then a 5% drop from e5 to e10 the drop would be a higher precentage each time you add additional e to the mix (these are not real numbers, just examples).

And as our motors wear more and more... It is not out of the realm to believe the drop in milage numbers would be even further exacerbated by the ethanol.


Absolutely everything else being suggested here (tire pressure, o2 sensors, cat conv, etc etc) are also definate potential contributors... but I think it's short sighted to look past the gas. I have personally noticed a difference when the summer blend gas here in CA goes in and out... not so much any more because I think they have us on summer blend (excuse to make it more expensive) year round now.

 

I guess I just don't have that much of a general disdain for the government in this case. They spew plenty of bad policies, for sure. Being that I'm one of those lazy yet willing do everything I can to lie about data government workers, maybe I'm biased.

What's funny though is that the testing I was referring to (my earlier link) wasn't even a government site, it was a trade organization, and they were citing work by various other trade organizations, along with the government studies and academic research.

My hatred for ethanol fuel has more to do with using food as a fuel, rather than, you know, eating it. But that's a different conversation entirely.

 

We should just compile a copy-pasta of all the common mpg issues on these things.

• o2 sensor(s)
• maf sensor
• cracked exhaust manifold(s)
• leaky injector(s)
• lead foot
• big heavy tires
• the wrong gears
• etc

Its really hard to guess without sitting down and looking at the vehicle and some data.

 

Could also be that every bearing in the truck is old and takes out efficiency, even one slightly bad idler pulley can hurt gas mileage by a little bit. Best way to truly check the difference of the gas or air quality etc would be to change every bearing, fluid, and piece of rubber, also a complete rebuild of the engine and transmission.

 

OP is getting the about MPG I get when I'm towing a 6x12 U-haul trailer. Something is obviously broken and you won't have to disassemble the truck to find it.