Why is my gas mileage so bad?

So I own a 2001 tacoma ext cab. Its s 4x4 with a 3" lift and 32" mud terrains. Automatic transmission and I drive like a guy in his 40's normally would. (well lets just say I dont rod and romp on the gas pedal to much)

It has a flowmaster 40 series which seems to have improved gas mileage. BUT. In town(90% of my driving) I only get about 13-14 mpg.

Its the 3.4 V6. btw-

Freeway with cruise control, I can push 19-20

 

Weird, do you have E load range tires? Those will definitely hurt gas mileage, but I wouldn't think that much. Maybe your O2 sensors are bad?

 

your driving style... try to hover around 2K RPM in around town driving - this includes accelerating from dead stop

 

Do you drive with the 'Power-ECT' button selected? Its a button on the dash, to the left of the steering wheel. when its engaged there will be a green Power indicator lit up on the instrument cluster below the fuel gauge.

Engaging the Power- ECT setting will change the shift points slightly. It will actually cause the auto to hold a gear just a little longer. For my driving style I found this setting improved my mileage by 1-2 mpg.

Try it for a tankful and see what kind of results you get.

 

Clean your thottle body (useing Seafoam Deep Creep) , maf sensor, air filter, check 02 sensors, Seafoam it and check your tire pressure. Should help out alot!

 

From my own experiences, your gas mileage is about the same thing I am experiencing. The 3.4 just seems to guzzle that gas in the lower gears. Maybe its just our Toyo M/T tires.

Your highway mileage seems to be about right on with others though, with over 300 miles to a tank. Usually city driving seems to be rated 5-10 miles/gal lower, so although the epa has your truck rated at 17 city/19 highway, I dont think what you're seeing is out of the ordinary with a heavier load.

Also, dont forget that unless you're adjusting for wheel size difference, your odometer may not be showing the correct distances, so your whole calculations may be off by a bit.

 

You don't have the problem I have...lead right foot mod

 

Yep. I know they do on the 2nd gens.

 

Tire size for sure, drop to 31s and you will see an improvement.

 

I understand the concept, but with the 3" lift going down to 31's would just look stupid. But I understand the concept. I run 31's on my truck with no lift and still don't get good gas mileage. But I have the 3.0 v6.

 

my dads t100 only get 14mpg on the highway sooo be happy

 

I guess the majority of my problem could be the fact that I only live about a mile away from my company, and I drive there and back 3 times a day

However, Im going to try to use Chevron Techron Fuel Cleaner and give my truck a cleanout, hopefully see some improvment.

 

Yeah, I would def. do a good cleaning on TB and MAF. But also If you haven't changed your o2 sensor's and you got over 100K miles. I would do that also. Thats the #1 thing that will make a difference. It helped get my mpg's from 14 to 16. But then they got fried and had to replace them again...Dont ask!

 

Not 100% sure how to change o2 sensors. Can a shop do it for me?

 

Well, the one mile thing doesn't necessarily have much to do with it, but more along the number of stops, how fast you accelerate, and your avg speed.

It takes more energy to start something moving than it does it keep it moving, so every time you have to stop and restart, you're burning extra fuel. Of course this isn't something you can necessarily control, but if you have 15 stops in that mile, that would explain explain quite a bit.

If you accelerate quickly to get up to speed, you're putting more a load on the engine and burning gas. (Although I accelerate slower than the vehicles around me, I still think this is the part that I could improve on a bit by watching the ScanGauge)

As far as your avg speed, if you're speed is fluctuating because you accelerate than coast, thats going to eat up gas compared to a constant even speed. (There is some theory about pulse driving like that, but acceleration stage is still very even and unless you have an engine cutoff, its not worth your time.)

What it really comes down to is if you have to press the brake pedal, you've wasted some of that energy that was spent getting to that speed. Of course its not practical to coast for 1000 yards before you have to stop, but if you let off the gas a little sooner than normal and watch how you accelerate, you may notice some difference.

btw, the ScanGauge has really changed the way I drive, as when used, you can see exactly how one action affects other aspects, and where exactly you can improve your efficiency.

 

Its really easy man! I got mine on Rockauto.com, they got good prices!

 

I still say do all the maintence stuff I posted. Clean your throttle body, Maf sensor, seafoam it, and 02 sensors!

 

Re-gear.

 

Your fuel consumption does not sound bad to me. Our stock Tacoma with 3.4 and the 5-speed gets 16-18 MPG.

 

My t100 with 290k I would still get 18 mpg all round and on the highway I would get at least 20 mpg doing 70mph