14mpg in 3.4L quad cab ?

My mpg is stuck at 14mpg for the last 4 tanks of gas that I calculated. truck is on 32 in tires. Recently fixed wheel bearings, dragging breaks, and upper a arms. Put in new air filter and no improvement. No check engine lights and recently passed smog. I have not aligned it but drives straight and tires appear to be wearing normally. What to look into. I should be getting closer to 270 miles per tank but closer to 220 now.

 

Sounds about right. You went up in tire size. The extra weight of the tire and size will affect your MPG.


By the way, what is your exact tire size?

https://www.fueleconomy.gov/feg/bymodel/2002_Toyota_Tacoma.shtml

 

When you calculate your mileage, how are you correcting for the extra tire height?

 

I have had the same tires for over 10 years used to get 270 to maybe 300 per tank last year or so has been about 230 per tank. I should have specified no ride height changes have been made recently. Trying to get ideas for why the drop. I thought it was the caliper drag and wheel Berings but no significant improvement with those changed.

 

Is that hwy or city mileage ? Sounds low to me either way.

 

Engine tune up time- clean MAF & IAC, new PCV, spark plugs, wires, fuel filter & injectors.

Do you have a ODBII reader/SGII to check the fuel trims?

I'd also be checking for any exhaust or vacuum leaks to ensure the sensors are getting good data.

 

Have you changed your driving habits? Are you throwing any codes?

 

I have always gotten 12-15mpg regardless of tires or setup, but ya you need to add a little bit for your tires

 

Not really any changes and no codes that’s why I’m asking here. Definitely a reduction TK mileage I used to get years ago

 

I have an OBD reader so I’ll need to look up what those are supposed to be at. No codes on anything tho.

 

Could be gas. Gas stations are running higher ethanol contain to try and fight rising gas costs. Down side is lower mpg. Both of my doubles cabs got around 15 mpg. Make sure your checking tire pressures.

 

I would love to get 14mpg... currently getting 8mpg

But it's SMILE PER GALLON for me.

 

I get 10ish but I'm on stock gears and 33x12.5s and supercharged with a lift and extra weight.

 

Heck, even 10 I'll take. Lol

I get 8 on the highway with a good wind. In town, I average 7ish if I'm lucky.

I'll idle and watch my guage drop, lol.

 

This would be my first move. I'd add checking coil pack resistance to that list too.

 

Hmm, it's been a long since I calculated MPG. When I used to it would be 14-16 average. That's with lift and 285/75 16 Duratracs.

 

So Glad I've kept my truck stock. I'm getting 23.5 mpg on the interstate with cruise control on 70mph. If I can keep my foot off the gas pedal, I can get 18mpg just driving around. I did have to change my plugs and wires to get my milage back to where it was. But with "Winter" gas coming, I'm sure my numbers will drop.

 

with 31” (or equivalent) tires the speedometer/odometer reads high.

I’ve found with 32” (or equivalent) tires the speedometer/odometer is damn near spot on.

To the OP - what is your driving style? Short city stop/go runs? This is an mpg killer for me.

 

I would look into the alignment.

Could also look at the thermostat....if its dead in the open position or weak, the truck will run in a rich condition until its warmed up thus wasting a ton of fuel. Make sure coolant isnt flowing before its warmed up.

Same for the cooling fan...check the clutch.

 

When mine was bone stock, still on factory installed tires, the best I ever got was 21 MPG. That was all highway. TRD 4.10 gears w/manual trans.