Need Help with my MPG

[rmjcvelez]

I just traded in my 03 4-runner for a 04 Sequoia-I needed additional towing capacity. The following are my MPG calculations with my new (used-with 18Kmiles) Sequoia:

Without a trailer
City 10.2 MPG
Highway 14.3 MPG (315 miles / 22.1 gallons= 14.25)

Pulling a 4300 lbs. trailer
6.3 MPG over mountains
7.3 MPG on flat straight-away


Something seems way off. I contacted the Toyota Dealership and they say that seems low, but not alarmingly low. I started thinking the electrical braking system on the camper was slightly engaged, but this was checked out by the camper dealership and ruled out.

When buying the Sequoia, I expected my gas costs to go up, however, this is unacceptable for a Toyota.

What should be considered acceptable for my MPG??? Any suggestions on how to conserve gas??? Someone mentioned synthetic oil-any specific brands??

I really miss my 4-Runner!!!

Thanks for all input....

[hill8570]

Yeah, that's low, even for a Sequoia. I feel your pain -- I bought a 2002 back in March, and my gas mileage has steadily dropped from 13.5 to 11.5 MPG (all in-town, no towing). The current tank is well on its way to being 10 MPG (halfway down, only 107 miles on the tank). Still trying to troubleshoot *why* without resorting to just shotgunning parts. At the moment, I miss my Taco like you miss your 4Runner .

With mileage like yours, I'd suspect something in the fuel control setup more than just subtle stuff like oil or tire inflation. Unless you've got 40 pounds of lead in your right foot. Any chance you can hook up a laptop-based OBD scanner to see what your sensor readings are? I'd love to have someone to compare notes with...

[rbjbbb]

I would assume some possible issues also. O2 Sensors? Dirty Air filter? Maybe run some fuel injector cleaner thru.

My observations on mpg are below. I have a 2001 with 39k miles. 2wd. Only have a K&N drop in as mod's. I believe the '04 has the same non vvti engine and same rated 240 hp. ps. I run Dino Oils. Run injector cleaner every 4 or 5 tanks.

3 most recent tanks. Running aroung north Dallas. I would say 75 % stop and go city and about 25% short hops on highways. No interstate travel.

I have run the last 3 tanks 'til the light comes on and then fill up when convenient.

5/25/06 - 343.3 miles 22.006 gallons - 15.6 mpg
6/3/06 - 338.0 miles 21.29 gallons - 15.87 mpg
6/12/06 - 336.8 miles 21.916 gallons - 15.37 mpg

(has gotten hotter so I blame more a/c and higher ambient temps on the fall off)

Hope you get her back into to acceptable range. Although 15 to 16 is not great, I feel it is acceptable considering the size and weight of the Sequoia.

Rb

[Larrison]

Whoaa.. that does seem low. I've got an '02 Sequoia with around 55K miles on it. I've been tracking and calulating my mpg for the last couple of months just for grins (spreadsheet).

My mileage varies from 19+ mpg (all interstate highway roadtrips) to my "normal" 13-15 mpg which is *all* city/ suburban driving -- 90%+ percent stop light to stop light driving. My most recent tank was 206 miles and 15.2 gallons

[imdav2u]

I also went from a 4Runner to a Sequoia. My mileage was around 14 city / 17 highway. I kept hearing about synthetic oils and their benefits on mpg's.After a lot of reading and searching the internet,I decided to give it a try. Mobil 1 was my oil of choice,that,along with the Mobil 1 oil filter.I changed the oil on a Wednesday evening,filled up with gas Friday morning and left for Chicago from St. Louis.With the cruise set at 70 all the way with one stop for food,I filled up when we got to our hotel.My figures ,checking them twice,came up to 20.6 mpg.I filled up again on Sunday for the trip home,same speed and again only one stop,this time was 20.5. I have been checking it the last 5 or 6 fill ups,driving around town and 9 miles to work, I have been getting around 16 1/2.I'm sold on fully synthetic oil.

[MarkHenry]

I bought a used 04 Sequoia 4x4 Ltd with 48k miles recently. When I First rolled it off the dealership's lot (a Toyota dealer) the thing was getting 14MPG. I replaced the o2 sensors, plugs, wires and electronic distributor, rotated the tires, replaced the oil and filter, air filter, and fuel filter. Total cost was about $250 in parts and an afternoon of my time.

I'm now getting 21.5MPG highway and 17 city.

Routine maintenance is key for continued good performance. I change my oil every 3k miles or 60-days, make sure the tires get rotated and have the right pressure, and hose it off when I get back from off-roading (I put about 1k miles a month on it on dirt roads in mid western Maine).

[-=tg=-]

Also, try a different gas station...with the way things are going these days...one never knows what the dealer's are doing to try and make a profit (believe or not, the dealers are getting squeezed, too...all the profits are going to the suppliers).

[rmjcvelez]

Something else I noticed over the past weekend-not sure if it would be related-whenever I accelerate, my oil gauge goes up to high. In other words, while sitting idle, my oil level shows a normal reading. When I accelerate, the needle moves to high. As soon as I reach a consistent speed, the needle drops to the low position.

By the way, thanks for all the input. I strongly believe my issues warrant the dreaded trip to the service department at Power Cerritos Toyota.

[uirx2002]

I just got 360 miles on 20.5 gallons, which comes out to 17.5 MPG. That included a trip from SE Denver to Breckenridge and back and 3 commutes to work. Not too bad. I'm going to continue to gauge it.

[endurance]

To get maximum value from this thread, it would be good to know 4WD vs. 2WD and stock rims vs. bling rims. Many say that you will lose 10-15% mpg for 4X4 and another 10-15% for the big tires like you usually see on 20" rims. So from hwy mileage of 20mpg, it's not shocking to lose 2 or 3 mpg for 4WD and another 2 or 3 mpg for the bling rims and the tires that go with them.

[cyaltr94]

That is true, I saw 3 mpg drop in summer on my GS when I switched to 20's.

Last tank I got 19.2mpg in Sequoia, strapping on 20's this week, we'll see what the drop is.

[pservano]

I average 17 MPG city. Highway, 21 MPG. Drove to Toronto, Canada last weekend spent approx. $100 of gas 750 miles one way. About 35-36 gallons of regular unleaded gas adding up the number of gallons on my receipts. Still have 1/2 tank left over when I arrived in Toronto.
I have 2002 Toy Seq Limited 2WD...

[DJ]

I suspect that your oxygen sensors are defective.

A short story explains why I might think that. Some years ago, my older brother was driving from central Missouri back to central Oklahoma after a deer hunting trip. His Ford pickup was still in warranty. Suddenly, it lost much of its power and gas mileage dropped remarkably. He called my other brother, who has been in the automobile business for decades, and who told him, "It's your oxygen sensors." The rest of the trip, he averaged about six mpg. The next day, he took it to the dealer, who changed the oxygen sensors under warranty. The truck was immediately back to normal, at about 18 mpg.

Now, why would oxygen sensors cause this problem? It's actually pretty simple.

The optimum ratio of air to fuel that is burned in the cylinders is about 14.6 to 1, meaning 14.6 parts of air to one part of fuel. If the ratio is higher, then air is being pumped through the cylinders without contributing to combustion, which wastes the horsepower required to pump the air, and so wastes fuel. If the ratio is lower, then fuel is being pumped through the cylinders without being burned, which wastes fuel. Either way, the result is less miles per gallon.

The engine uses an "MAF", or Mass Air Flow sensor, to measure the rate air flows into the engine. It opens and closes each fuel injector in time with the engine to inject and vaporize fuel into the incoming air at each cylinder. It varies the amount of time each injector is open to vary the amount of fuel each injector supplies, and it does so based on the measured rate of air flow.

So far, that's an "open loop" system. The fuel mixture would be correct if the MAF is calibrated accurately, the fuel system pressure is correct, the injectors are clean, and so on. But, what if things aren't "correct"?

That's where the oxygen sensors come into play. The engine control system senses the amount of oxygen in the exhaust gas at the headers and uses the measured oxygen content to "close the loop". If the oxygen level is too high, then the air/fuel mixture is too lean, and so it opens the injectors for a longer duration. If the oxygen level is too low, then the air/fuel mixture is too rich, and so it opens the injectors for a shorter duration.

This works nicely, as components can deteriorate and yet the system will keep the mixture correct. But, it works only so long as the oxygen sensors accurately measure the oxygen content. If the oxygen sensors measure more oxygen in the exhaust than there really is, then the system will supply more fuel to make the mixture richer. If the oxygen sensors are way off, then the system will supply way more fuel than is necessary, which results in really low gas mileage.

I think that's what's happening in your truck. If it were my truck, I'd replace the oxygen sensors, regardless of whether or not warranty covers it.

Incidentally, I made that same trip to Missouri and back 10 days ago in my '00 Tundra and I got 18.5 mpg.

[maddogsvolusia]

I just replaced all 4 of my O2 sensors trying to get out of the mixed driving 13s in my 2wd with 265/70/17 Bridgestone Revos. (The front Driver's 02 was a nightmare by the way! Galled threads had to be destroyed and retapped!) Anyway, no improvement. I use a K&N air filter, Synthetic oil, and recently tried NGK V-groove plugs. I also run Primrose injector cleaner in every 3000 miles. I keep the tire pressure at 38 to 40 PSI. My next step is synthetic in the transmission and differential. I seem to have plenty of power, I just can't break 13 mpg in mixed driving or 15 mpg highway. It's not terrible for how nice it rides and all the space, I would just like to do a little better. My 12 gallon car can drive farther on a tank of gas than my 26 gallon Sequoia. hehehe

[mmikulak]

Ouch !!

My computer says I get 17.2 avg with mostly hiway mileage and A/C. I calculate 15-16.8 normally.