gas milage

[wmeza1]

Hey.
So I have a 3rd gen 1998 4runner and in the last couple of weeks my gas milage has gone from around 310 miles to a full tank, and now its giving me only about 200 if lucky. any ideas?

 

[kolbydmc]

310?!? The most I've ever got out of mine on a full tank was around 230. I'd love to see 300 + miles!

 

[PitbullRescuer]

Could be a ton of things. Do some searching on here, there are a lot of threads.

Some common culprits:
Bad plugs
Bad wires
Dirty MAF sensor
Dirty Throttle Body
Bad O2 sensor
Carbon Build Up in the engine
Dirty Injectors
Clogged Catalytic Convertor
Exhaust Leak
Rear Brakes Sticking
Front Diff Actuator Locking the Hubs in 4WD
Worn bearings in the rear axle
And probably some other things I'm forgetting.

 

[T4R_MTL]

I got a 4 banger and I only get around 250 so you're lucky to have gotten 310..

PitbullRescuer pretty much has the list of things to check.. I'd start with cleaning the MAF censor

 

[ellner357]

Could be a ton of things. Do some searching on here, there are a lot of threads.

Some common culprits:
Bad plugs
Bad wires
Dirty MAF sensor
Dirty Throttle Body
Bad O2 sensor
Carbon Build Up in the engine
Dirty Injectors
Clogged Catalytic Convertor
Exhaust Leak
Rear Brakes Sticking
Front Diff Actuator Locking the Hubs in 4WD
Worn bearings in the rear axle
And probably some other things I'm forgetting.

What's the way to tell if the front diff actuator is locking the hubs in 4wd?

 

[02_SE_Runner]

I agree with Pitbull's post. Some of you have never gotten 310 before? I get a good 300 miles before my light even turns on.

 

[aleks77]

hmm im only getting 210 miles to a tank (well to 15.18 gallons), 13.8MPG. But this is 90%+ city driving. Ive done everything but o2 sensor/injectors/seafoam. Truck has 90k miles. 3.4L

 

[smkd13]

Could be a ton of things. Do some searching on here, there are a lot of threads.

Some common culprits:
Bad plugs
Bad wires
Dirty MAF sensor
Dirty Throttle Body
Bad O2 sensor
Carbon Build Up in the engine
Dirty Injectors
Clogged Catalytic Convertor
Exhaust Leak
Rear Brakes Sticking
Front Diff Actuator Locking the Hubs in 4WD
Worn bearings in the rear axle
And probably some other things I'm forgetting.

Add:

fuel filter
oil
tire pressure
alignment
bad fuel (yes from gas stations)
bad coil

I was getting 285 to 340 off a tank but my speedo was off so naturally the odo is off but after lifting 3", 33" E-rated duratracs, 4.10 i am getting almost 300 a tank (GPS trip calculator). 17.2 average.

pretty much all that stuff will throw your mileage off. if you want to have a good starting point then then i would start with you O2 sensors, MAFs, spark plugs, SP wires, fuel filter, and pcv valve. roughly will cost you 100 to 200 dollars but it is a good place to start and gets rid of a lot of routine maintenance that might have been neglected.