this isnt the typical and much hated "im getting bad mpg" thread so Im going to dare throw this out there to the 4runner family to see what you think...anwyay, I finally got the go-ahead to spend a little money and get a 4runner. Ive wanted one for a long time and found one that I thought would be perfect...low miles (119000), 2000 lmtd, seemingly great shape. It, starts, idles and runs like a dream but ....
... 5 mpg and 6 mpg in city driving... The big selling point to the Mrs. for me trading in my 4wd fullsize pickup was " Ill be getting much better gas mileage than that old truck" so the savings were supposed to justify the extra cash needed to buy it....
Ive read for hours on here all the possible culprits to bad mpg so I dont know if there is something Ive missed...i guess my question is this... does anyone have an idea if there is a major culprit at work here with my vehicle? it has not thrown any codes so its anyone's guess... if all fails I guess my wife's suggestion of using it as my "personal sleeper" instead of my daily driver might come into play.

What type of commute? If it's short and the vehicle never gets to temp you'll get horrible mileage.

My first question is, how are you calculating that?

What kind of driving do you do?

5-6 is insanely low. That means you're only gettin 108 miles from a tank? When is your low fuel light coming on?

I've been working on this a bit lately. Here is what I've done, or will be doing in the new future.

*new air filter
*new fuel filter
*clean or new MAF sensor
*new upstream sensor

With my experience driving in the cold we've had in St. Louis this year. I've notice around a 35% decrease in MPG in cold weather.

Is that 5/6 MPG a real world value or are you underestimating it? I know 4runners don't get awesome gas mileage but really only getting 100/120 miles a tank in city?? That just don't sound right if it runs great..

Yes, my drives are short to work, less than a mile but I've also went on some short jaunts out of town etc just to run it a bit...but i do let the engine run for about 10 minutes before taking off each time I start it. It has been cold here -20 to -10F about every day since I picked it up 10 days ago. the way ive been calculating it just using the odometer -- driving 30 miles, and then refilling..both times it took more than 6 gallons to fill. Perhaps that's just the nature of the beast. I am having the rear drums looked at later this week, looking at bell crank tutorials on here in case that's an issue.

I bought my truck in October and have been working on the checklist below. Some may disagree with a few of the items, but I've been happy with the results. A recent trip from Nashville to Chicago and back including some city driving and awd during a snowstorm netted me 19.5 mpg for the whole trip.

You've probably already seen the checklists on similar threads, but here goes anyway:

Fuel filter
Clean the injectors and fuel system*
Frequent oil changes (I've been using Mobil 1 5w30) to help gently clear any sludge
New plugs and wires
Differential oil change
Maf and throttle body cleaning
EFI reset
Remove running boards
Remove luggage rack cross bars (unless you actually use it)

*I called the dealer to ask about having an injector service done and he recommended that at my high mileage (180k) that there was a risk of causing problems by knocking cuff loose suddenly. What he suggested was every third tank or so, fill it with premium, put in a good detergent fuel additive and gun the shit out of it going onto the highway some. He said that would serve as a more gradual cleaning.

Short drives + long warm ups could easily result in the MPG you're getting. I'd wait to check it out on a couple of longer drives before you assume there's a problem.

This made me laugh! I had to replace mine, and seems to be a pretty common thing as well. You can get a complete set from O'Reilly's for about $40.

5mpg? holy moly crapoly.

Ok.. thanks for all the responses and ideas.., much appreciated... and there were a couple suggestions that I hadn;t come across before.. Cash flow is at a premium now (teacher) so throwing a lot at it with upgrades etc would be a very slow process so hopefully with a few minor things tried it will improve. thanks again.

I agree. Best thing for mileage is to get in, start, wait 30-60 seconds and take off. Letting it idle for 10 minutes and then a short drive is going to kill your mileage. You're going to have to drive for a full tank on longer distances before the computer will truely reset and start conserving the fuel.

This is probably the main reason for your poor MPG.

There's your answer: The short drive to work. Letting it sit there and run for 10 minutes in cold temps before driving less than a mile each time. Finally, the cold temps means all of the fluids in the drivetrain are thicker, which means more drag until they reach operating temp. Which with your driving they never do.

You described the perfect circumstances and practices for getting bad MPG.

You might also consider using a lighter weight oil, like a 5W-30 instead of 10W.