My Gas Mileage Sucks! Help!

[NViejeP]

I filled up my tank when the gauge said it was empty. I filled up 14.8 gallons. The meter went up all the day to full. Right now, I'm at below half way mark, but above the next mark (1/4 or 1/5). I have 97 miles on this tank of gas.

Here are some facts about me and my car:
-I drive a 2000 T4R. I purchased it used at 68k miles. Right now it is at 68800 miles.
-My air filter is stock and is very clean.
-My oil level is between those two markings, the color of the oil is golden or light brown.
-I sometimes do hard accels, and sudden stops. I once in awhile floor it. But recently, I've been driving softer and not as hard.
-My PSI right now is at 33-34. I just filled it up from 26 yesterday. I have 31x10.5x15 tires. The maximum tire PSI is 40 or 50.
-In San Francisco, the mornings are cold, and the weather is generally cold, it does warm up latter in the day. But only somtimes. But sometimes it is warm.
-I do not use ETC, I have stock everything except head unit lol.

Would anyone recommend anything to get better gas mileage? Could it be the fuel gauge meter out of synch?

 

[greasefingers]

Absolutely could be the dash board gage. On my Jeep, when the gas gage reads half empty I am completely out of gas!
What is your gas mileage calculated from miles traveled divided by the gas pump volume? This is the only way.

 

[sharp4runr]

Well what is your gas mileage? The way I calculate it is dividing the number of miles driven, by how many gallons of gas was used. What I do is fill up the tank. I reset my trip meter. The next time I top off, I record the amount of gallons it takes me to fill up (This is how many gallons of gas you used) and how many miles were driven according to your trip meter. Also it is important to know if the tires you have are the stock size tires that came with your truck. If they were upsized/downsized, this will throw off your tripmeter and you'll have to adjust accordingly. Without knowing what your actual mileage is, how can you say it sucks?

Some suggestions to increase mileage:

Keep tires inflated to proper PSI.
Overinflate tires. This reduces the contact patch of the tire slightly thus reducing drag from your tires.
Switch to synthetic fluids if you haven't already done so
Easy accelerations (No "Jack rabbit" starts)
Use cruise control
Get a free flowing exhaust (too early to tell for me, but it is suppose to give a bit of a boost in mileage if you can stay off the go pedal)

See my sig for my gas mileage spreadsheet. Yes I know it's anal to keep track but I don't care. I like to see the numbers (sometimes).

 

[NViejeP]

I haven't calculated mileage yet. But so far I've filled up 14.8 gallons at the pump which topped it off. And so far I've driven 100 miles and its down below halfway. Which makes me worried.

The tires are different from stock. I believe stock is something like 225/x/15 - mine are 31x10.5x15.

I will switch to synthetic when I can.

 

[Jacobzky]

See my sig for my gas mileage spreadsheet. Yes I know it's anal to keep track but I don't care. I like to see the numbers (sometimes).

that is nice to have a statistical data of your fuel consumption, nice idea, i might start doing that too. i too track my gas mileage, but its all in the head, but it hard to recall. all of them.

 

[sharp4runr]

I haven't calculated mileage yet. But so far I've filled up 14.8 gallons at the pump which topped it off. And so far I've driven 100 miles and its down below halfway. Which makes me worried.

The tires are different from stock. I believe stock is something like 225/x/15 - mine are 31x10.5x15.

I will switch to synthetic when I can.

Well there you go. You may THINK you've driven 100 miles but for all you know, you've driven 175 miles. Your odometer or tripmeter is assuming that you are using the stock size tires. Looks like you have to do more work to figure out if you are indeed getting "sucky" gas mileage. It's like saying the weather sucks when you haven't looked out the window yet :

 

[toto]

Well there you go. You may THINK you've driven 100 miles but for all you know, you've driven 175 miles.

Tire size is a factor, but that's exaggerating a bit. Size shouldn't make more than around 5% difference, or 5 more miles out of 100. Toyota adjusts the ECU to deal with any size tire that might be an option on the vehicle (without mods like lift kits). So the computer's not 100% accurate even with the "right" tires, but it's close.

The fuel gauge sounds more likely, but to check that out, compare the amount of gas you put in to the size of the tank. And keep in mind that the gas gauge is very conservative - there's probably 3 gallons left when it says Empty and the light comes on. You said that you put in 14.8 gallons when it said "Empty". That's right if it has a 17-18 gallon tank, but that's too low if it's got a 20+ gallon tank.

If there's a problem with the fuel tank sender, the gauge won't drop smoothly consistently from Full to Empty. There might be a period where it doesn't move, or it might drop dramatically.

 

[Uneek]

Every car and truck we've owned the gas gauge didn't drop linearly. If total range was calculated based on consumpation at 3/4 full and half a tank, it would nearly add about 30 miles to the range we can go.

My Tacoma, at 3/4 full would be at about 80-90 miles, by half it's about 150-160. But when it's down to 1/4 to empty it's only got 280-300. Same with my Camry, at 3/4 it's about 100 and at half, it's only about 170. The highest I've gone between fill ups with the Camry was about 380 with the fuel light on, and I was hoping to break 400. Both are based freeway driving at about 70-75mph.

I top off slightly (2-3 clicks after pump stops, adding maybe 1/4 gallon more) when I fill up. It goes a tiny bit past the F. I was never able to do this on the '90 Toyota truck, even if gas spilled out of the filler, it wouldn't go past F.

 

[NViejeP]

So, my tank emptied at around 130, or at least it said empty. I bought 14.8 gallons for 130 miles.

Which is less than 9 miles per gallon. Problem is that I filled up again with only $10 worth of gas becasue my atm card wasn't working and I only had like $15 of money on me. So I couldn't actualyl see how many gallons I could fill in that tank.

So I'm PRAYING that it is either a one time thing like that one guy said, OR my meter is terribly off and I'm going to fill up only like 10 gallons worth of gas next time I try to top off.

 

[Northof49]

It's the guage....common problem in those years.

I believe the actual problem is the sending unit and there is an upgraded part/part number for the problem part. Dealer should know, it's common.

 

[NViejeP]

So I actaully have a lot mroe gas when it hits empty than usual? And by how many gallons is it usually off?

 

[greasefingers]

Calculate your actually gas mileage. Then calculate how many miles you can run off one full gas tank. Then back calculate how many miles you can travel leaving 3 gallons of reserve fuel in the tank. Now reset the trip OD and fill up every time you hit this mileage.

The only other option is to drop the tank and replace the sending unit.

 

[RonMAIDEN]

Tire size and load range can affect mpg because of weight. Most passenger truck tires are in the C load range but my Nittos are D which are heavier and my mpgs dropped a tad after installing them.

 

[Northof49]

So I actaully have a lot mroe gas when it hits empty than usual? And by how many gallons is it usually off?

I'm not sure if there's a "usual" amount.....but generally the first 1/2 of the tank would go too fast according to the guage, and there would be lots left in the tank even on gas light.

Of course, the only way to find out is the calculate it out.....if you find that you're mileage isn't bad, but your guage is reading empty, it's the guage.

 

[jmtreetop]

I would bet that your oxygen sensor is bad. This happened on my 98 4runner. While I normally got 18-20 mpg I was suddenly getting 9mpg. A bad oxygen sensor will cause your engine to run rich, hence more gas.

 

[NViejeP]

Well, I've talked to some of my friends with sedans such as Passats and one with an old BMW, they said that they usualyl fill up once a week, to once a week and a half. The ysay they get like 150-175 miles per gallon.

Their situation is like mine, we drive mainly all city with VERY little highway.

Is it possible that like 140 miles ALL city is normal for a 4Runner?

 

[sharp4runr]

The ysay they get like 150-175 miles per gallon.

Wow, what's their secret? : That's a lot of miles to the gallon. I'm sure Honda/Toyota would love to get in on the secret...

I just filled up and about 15 gallons approximately tonight and drove about 276 miles with it. That calculates to about 18 miles to the gallon. On my trip computer it estimates that I can get about 400 miles on a full tank of gas (23 gallon tank on the 4th gens).

You need to start getting hard numbers down and calculating your mileage. Otherwise, you're just guessing on your mileage...

 

[Uneek]

Is it possible that like 140 miles ALL city is normal for a 4Runner?

Sorry, I don't mean to sound harsh.

14 miles per gallon in all city driving, yes. But it varies with driving styles/habits.

140 miles per gallon, I'm not aware of any gasoline vehicle being able to acheive this, including motorcycles.

Perhaps your friends mean 150-175 miles per fill up. With a smaller tank like a 15 gallon tank and a 3 gallon reserve, typical fill up would be about 12 gallons, then it's about 13-14mpg.

 

[NViejeP]

Haha yah I meant 150-175 per fill up. Twisted my words a lot.

I just filled up my tank to full at 13.8 gallons. No topping off.

 

[RonMAIDEN]

I just filled up with 13.8 gallons with no topping off also this morning and my tank was at 217 which was a whopping 15.7mpg. I'm a little bit of a leadfoot and I have the inch bigger Nittos which are also a kind of heavy D load range tire.

My mom drives a bone stock '99 Limited and she sees about 260 miles a tank on about 15 gallons of gas gallons for a decent 17.3mpg.

We both live in the same area and drive the same amount of highway/city which is mostly city.