Hey Folks,

Lovin' my '00 4runner since picking it up 2 months ago - runs great, no leaks, smoke or any other issues that I can tell, but it's really costing me a fortune to drive this thing in it's current state. The car is averaging about 11-12 miles to the gallon, and I can't figure out why. It's got 172K orig miles, and the fuel pump/filter and just about every other filter was replaced in early June of this year. I've tried low octane and high octane gas, and basically get the same result.

The other day I had a 1/4 tank, and added 3 gallons, which put the gauge just a hair below the half tank level; then drove 12 miles from the gas station, stopped, and the fuel gauge was barely above the 1/4 tank level (WTF). Drove another 6 miles after that, and the gauge was well below the 1/4 tank zone.

For a 4 cylinder, this just doesn't seem right at all.

I was thinking about trying something like STP fuel injector cleaner, but wanted to get some advice or thoughts about going that route before doing so, as I'm a Toyota/4runner clueless newbie!

-get a tune up?
-try seafoam
-maybe a garbage cat converter
-clean MAF sensor
-don't break 70mph lol

I have a 4 cylinder as well. I've got 285 mt/r kevlars and i'm getting 16mpg. Granted I have a manual and I still haven't regeared, so I'd definitely get your truck checked out.

If you or somebody you know has an ODB reader I'd check that out first and see if you're throwing any codes. I have a lightly modified 4x4 V6 and I'm consistently getting 18-21mpg so you're 4 cylinder shouldn't be as bad off as it is. Here's the new purchase tune up I did:

New bosch p4 plugs
New plug wires
oil change
trans fluid change
clean out throttle body and adjust throttle cable
Front and rear differential fluids
Sea Foam the intake (do this first as I've heard it can foul plugs)
Cleaned off the intake filter (replace if you have a factory intake)
Fuel injector cleaner is recommended at every oil change
Replaced all the accessory belts (not necessarily going to help mpg but not a bad idea)
Rotate tires if it hasn't been done recently

Here's a few resources on how to do it:

How to: Change Drive Belts 3.4 L 5VZ-FE - YotaTech Forums
4Runners.org - Maintain it. Mod it.

A wore out front O2 sensor won't always throw a code but will give crappy gas mileage. When was your's last replaced?

I use fuel injector cleaner every time I do my oil just for peace of mind.... if it even does anything could easily be debated either way.

Just a side though.... Are you actually calculating your MPG's by the ODO/gallons purchased, or just going by the fuel gauge? I know alot of us have some screwy fuel gauges (saying empty when 3+ gallons left, going super fast/slow at certain intervals, ect).