Decrease in mpg
 

I have a 2000 4runner 4wd v6 and have noticed over a few weeks that I am getting between 3-7mpg less than usual. I have around 100k miles now and think maybe some things such as fuel filter and plugs and wires need to be changed. I am the second owner so I dont know if these things have been done. Any suggestions, do those fuel additive injector cleaners and engine treatments work or can they be harmful for our 4runners?

Deffinatly start with the basics- plugs, wires, etc. get the oil changed and the tranny and differentials flushed.

I also am interested in everyone's opinion as I just checked the mileage in my 97 I just bought and estimated around 14 mpg around town. It has 144K and I'm sure it needs a minor tune-up, hope that helps I was hoping to get around 18-20

16-18 really is the norm for in the city with a high of 22 highway but there will always be somebody who get's slightly better and slightly worse.

In the summer I get almost 18 in the city with my lead foot but that drops to 16 in the winter and occasionally I'll see a 15 or even 14 if I have to use 4wd a bit.

Where is the best place to get these parts. Im sure the dealership is pretty expensive. I hear the wireset for autostores does not compare in the oem one is this correct?

I've seen about a 1.5-2 MPG drop since they added 10% ethanol to the gas in Washington state.

Plugs definitely...think the 3.4 has coils for each plug, check them too. And new fluids. May or may not help with the mileage but its a good thng to do regardless if you dont know if the PO did it...

Definitely do a tuneup. Seasonal gas blends can easily account for 2-5 mpg changes.

Paul

that can be winter gas, or gas with a a good chunk of alcohol in it


it kills me 2-4mpg

Someone told me recently that they had their injectors removed and cleaned and are getting way better mpg. Not sure if that would work on a 3.4 or not.

Probably not your issue but I'll throw it out there anyway. After a long winter a few years back, my e-brake started to drag as the bellcrank got dirt and corrosion in the pivot and it refused to release all the way. This effected my gas consumption as well as my rig felt a bit down on power. I realized what was going on when I arrived at work one day and noticed that my rear wheels were smoking slightly and they were very hot. Once everything was freed up, mileage and power was back to normal.

as i get close to the oil change time, my mileage has dropped 0.5 - 1 MPG.
goes right back after a change.

I dont think it is the ebrake but I do hear what sounds like a marble rolling around in the cargo area which I heard is the fluid in the axle or drivetrain has leaked out, can this account for the loss of mpg. I figured seasonal gas would attribute to a few mpg loss.

I'm in support of a good tune up, like the others. I just purchased my 4Runner in Dec. and have run Techron through the fuel system and replaced the air filter. My milage is better by about 50miles/tank (sorry, haven't done a MPG calculation yet).

The ballbearing sound can be a sign of low or improper octane, depending on where the noise is omitting from.

A while back I did have the CEL come on and throw a TPS code. Could a bad tps be the culprit in lowering my gas mileage?

check your tire pressure....you can pick up some MPG right there.