Awful MPG 99 4Runner Limited

[badams1897]

I am getting horrible gas mileage in the 99 4Runner like 12. Am I doing something wrong? The engine runs great, sounds great. I have kept my foot out of the gas this tank hopefully it will improve. Am I in 4wd and I do not know it??

 

[raydouble]

I am getting horrible gas mileage in the 99 4Runner like 12. Am I doing something wrong? The engine runs great, sounds great. I have kept my foot out of the gas this tank hopefully it will improve. Am I in 4wd and I do not know it??

Is the check engine light on?

How many miles?

 

[IanB]

Are you talking city or highway driving? I don't think that's outside of what you should expect around town unfortunately.

 

[SRSRunner]

even with the ECT on?

 

[NOR CAL CRUISER]

12MPG is a little low. my 98 4 runner gets about 14mpg, 16mpg at its best! check you t-case make sure your not in 4-high and dont know it. my 4 runner has a light in the dash that tells me its in 4wd.try a tune up, oil change,plugs wires.tire pressure can also affect mpg.

 

[badams1897]

No check engine light at all, new O2 sensors 177k miles, new oil, new diff fluid, new tranny fluid, new bearings, 40PSI in tires, new tires. New plugs, and wires done at 120k mi. ECT on or off better?

 

[raydouble]

No check engine light at all, new O2 sensors 177k miles, new oil, new diff fluid, new tranny fluid, new bearings, 40PSI in tires, new tires. New plugs, and wires done at 120k mi. ECT on or off better?

People have reported better MPG with it on and not putting your foot into it.
Ever change the fuel filter?

12-15 is fairly standard for in town driving.

 

[badams1897]

So I ran it until fuel light came on filled it up and it only took 13 gallons. I drove it well past the E with the fuel light on pushing it. How on earth can there be 5 gallons in reserve? I think my gauge is off.

 

[raydouble]

From the FAQ

TSB EL010-00 Fuel gauge inaccuracy
TSB EL010-99 Fuel gauge recalibration procedure (text description of the procedure in the .pdf file as I couldn't find the original)

 

[Brake Weight]

Do you have a K&N filter? The oil messes with the MAF sensor causing bad mileage.

 

[SC T100]

Also, if you have taller-than-stock tires and you are reading from the odo, your calculation will be off (low mpgs...it will read fewer miles traveled). If you have oversize tires, check your distance with a GPS.

 

[KayakPanic]

redo plugs and wires if its been 50-60,000 since last changed, also change air filter and fuel filter.

If it has a distributer cap and rotor do those too.

If it is an auto, you might see if the AT filter(s) has been changed or cleaned. Usually a tranny flush does not include filter changes...

 

[raydouble]

redo plugs and wires if its been 50-60,000 since last changed

Plugs are due every 30,000.

 

[RobMikulskis]

check the air filter, maybe a small investment in a throtle body spacer or a cold air intake would do the trick

 

[Duane]

What does your tailpipe look like? black and sooty or very little residue and grey/shade of the pipe material?

Does it seem to coast fairly well when you get off the gas or does it seem like a brake is dragging?

Is it sluggish to drive? Acceleration ok?

Have you ever cleaned the injectors/ran cleaner through it?

Ever cleaned the MAF sensor?

I assume it is a 3.4L V6?

Anyone ever heard of a converter plugging up on these units?

What rpm does it run at what highway speed... wondering if lock up converter is working and OD? auotmatic I assume or a standard transmission?

 

[badams1897]

It drives ok, coasts fine, accelerates fine. I am going to look into fuel gauge and put a new air filter in.

 

[Duane]

Not sure how the accuracy of a fuel gauge helps mileage? range yes.

 

[Brake Weight]

There was a run of F150s that had gas caps that would go 'bad' causing poor mileage. Don't know if Toyota ever had that issue, but my VW threw an error once with a dash light that's an icon of a gas cap. I had to get it reset, but mileage wasn't affected.

 

[SRSRunner]

12-15 is avg from what ive read for "town" driving, I run with my ect on and have yet to get worse then 16. I avg almost 18 The maf could be dirty, but theres no way its going to affect your mileage that much, if it was bad enough to cause problems it would throw a code. Youve already addressed the plugs etc- which thats about all you can do, maybe check em since it easy to do.. Guess your one of the few who gets poor mileage.. read up on it, theres plenty of guys in that 12-15 range, and as high as 21-22.

 

[badams1897]

Update - I was figuring out mileage based on 18.5 gallons use like an idiot. I filled up, drove, filled up again noted gallons of fuel used and I am averaging 18/19 MPG highway. My bad.