Is your gas mileage as bad as mine?

[Nunyabiz]

In 100% city driving I get around between 12.8 to 13.2mpg.

100% highway is get between 17-21mpg depending on where I am driving.

 

[krenaud33]

Uhm what? Why does he need to replace the head gasket exactly??

I have read a few of that guys posts and I don't think he has a clue about much of anything. :laugh:

 

[gamefreakgc]

:focus:

This is not a "post your mileage" thread, the OP is looking for help!

This was my first thought. I'm surprised it wasn't brought up sooner.

OP- If you have a bad (including a poor seal) O2 sensor, your gas mileage can be affected by that alone. The O2 sensor, in the big picture, measures how rich or lean your engine is running based on efficiency. Of course, with any other OB1/2 vehicles, there are many other factors that come into play, but this is definitely something to look into.

This is spot on. If you gasket is bad, outside air could be getting in. Here's why it is bad:

• Gasket goes bad, outside air enters the exhaust and affects O2 sensor
• O2 sensor sees "unburnt" oxygen in the exhaust gases
• O2 sensor increases fuel trims to compensate for excess oxygen reading
• You get poor mileage

Clean your MAF sensor. It's easy to do and does make a difference.

Also, O2 sensors don't' last forever, especially the front. If they are the originals from the factory, it might be time to replace the front O2 if you want to try and recover MPG's. On the 2nd Gens Toyota said to replace every ~100k miles.

 

[jreask]

In Torque, under Settings then OBD2 Adapter settings, enable "Faster communication" and also "Enhanced MPG Calculation" Otherwise it is WAY off

After checking it by hand for a few tankfuls I also set the MPG adjustment value under my car profile to 1.04 but depending on your driving that number may be different for fine tuning it.

Thanks for that tip. I'll try it and post up the results.

 

[73Duster440]

In my stock 98 3.4 auto 2wd I get consistent 10.5-11.5 MPG fill with 15 Gal each time and get 185-200 miles a tank.

I decided to hook it up to a genesis scan tool
Found that my O2s are faulty causing the motor to run excessively rich

Supposed to be around 1volts if operating correctly
Higher than 1volt it will run lean
Lower than 1volt it will run rich
Mine were reading .002-.004 volts

I am purchasing the 2 sensors in the next few weeks which should bring my MPG back along with Bosch Plugs and Wires, Seafoam and, oil change with full synthetic and 1qt of Hyperlube<This stuff Rocks
As well as the cat(Rotten Egg Smell=HORRIBLE!!!) and toss a borla muff on

Side note: The O2 before the cat does all the work and the one after the cat just kicks the CEL

 

[Tek23]

[MENTION=118879]Tek23[/MENTION]... when you fill up your tank from empty, how many gallons to fill up? There could be a good chance your tank sensor (forgot what its called) need replacement.

Example: when I purchased my 00 3rd Gen, I was noticing to fill up the tank was 13 gallons from the needle hit empty with light indicator on (about 197/200 miles). We should be getting 18 gallons from specs, so I got Scangauge and been monitoring and slowly increasing my Gallon settings from 13 to 16 gallons now. I haven't gotten stranded yet at 267 miles. My next fill up, I will set 17 gallons on the settings and run from there.

Basically what I'm saying is to ignore the light indicator and run it dry. To be safe, get a ScanGauge or another type, and monitor your fuel consumption.

My light comes on around 170 miles, but typically drive another 20 miles, give or take, before putting 13.9-14.3 gallons of gas.

Compression test will tell you everything. If those #s looks good, I'd hook up a scanguage or torque to monitor what the a/f ratio is doing, check for any codes, fix the sensor gasket, clean the maf and iac also. Luck! :cowboy:

Thats my last resort. Scared to see the results, as if i’m headed to the clinic to get myself checked lol

Front or rear O2? If it's the front it could very well screw up your mileage.

Rear sensor

:focus:

This is not a "post your mileage" thread, the OP is looking for help!



This is spot on. If you gasket is bad, outside air could be getting in. Here's why it is bad:

• Gasket goes bad, outside air enters the exhaust and affects O2 sensor
• O2 sensor sees "unburnt" oxygen in the exhaust gases
• O2 sensor increases fuel trims to compensate for excess oxygen reading
• You get poor mileage

Clean your MAF sensor. It's easy to do and does make a difference.

Also, O2 sensors don't' last forever, especially the front. If they are the originals from the factory, it might be time to replace the front O2 if you want to try and recover MPG's. On the 2nd Gens Toyota said to replace every ~100k miles.

I’ll clean it this weekend. Looking forward to winter being behind us.

 

[nissanh]

Just came home after a long trip. At around 75 - 85 MPH, I get about 16.7 to 18 MPG.

 

[SpidermanGeek]

:focus:

This is not a "post your mileage" thread, the OP is looking for help!



This is spot on. If you gasket is bad, outside air could be getting in. Here's why it is bad:

• Gasket goes bad, outside air enters the exhaust and affects O2 sensor
• O2 sensor sees "unburnt" oxygen in the exhaust gases
• O2 sensor increases fuel trims to compensate for excess oxygen reading
• You get poor mileage

Clean your MAF sensor. It's easy to do and does make a difference.

Also, O2 sensors don't' last forever, especially the front. If they are the originals from the factory, it might be time to replace the front O2 if you want to try and recover MPG's. On the 2nd Gens Toyota said to replace every ~100k miles.

This is next on my list because I am getting horrible gas mileage. The average MPG shown in my fuelly badge even takes into account the variance in my odometer from my 285/75's. (I calculate my trip meter as Reading x 7.27%). Yeah, I'm getting under 11MPG.

So New O2 sensors for me (I'm changing both), then a MAF and TB cleaning, then fuel and air filter replacement. I'm gonna try and do it all at once and reset my EFI relay. Hopefully I'll see an improvement then.

 

[Weetabix]

Pardon my ignorance, but what is ECT? How do you turn it off?

 

[Nunyabiz]

This is not a "post your mileage" thread, the OP is looking for help!

I think the point of those of us listing just their mileage is just to show that 13-14mpg is NOT low enough to where there could be anything you can do about it.

I thought it was when I first got this truck, however after doing EVERYTHING possible my mileage in city I do not think changed more than 0.5 mpg.
So short of maybe going back to 100% stock tires and height there is nothing to do that is going to make any difference.
13-14mpg especially depending on WHERE you drive is totally normal.

Now if he said like 9-12 mpg or less then I would think that there has to be something that could be done to get it at least UP to 13-14 unless he made a "Monster Truck" out of his 4Runner.

 

[krenaud33]

Pardon my ignorance, but what is ECT? How do you turn it off?

Electronically Controlled Transmission. There is a button on the dash to turn it on or off.

 

[Weetabix]

Ah. I have a standard, so no button.

 

[NCrunner2012]

I get 16mpgs, but that is with 265/76/16's that are load range C. I was able to squeeze 19 with my stock tires. I don't think that 14 is really that low.

 

[gamefreakgc]

Pardon my ignorance, but what is ECT? How do you turn it off?

ECT is the switch on your center console (or might be somewhere else on newer years) that says "ECT Power". It changes the shift points which makes towing and going uphill easier.

 

[Blitzkrieg]

A well tuned 3rd gen 3.4 should average 16-17 MPG combined.

That's normal driving. Not *****-footing around but not lead footing it. Just normal, sane driving.

 

[sandracer33]

I was getting consistent 17 - 19 mpg with 255/85-16. Then I put superflex springs in the rear & raised the front coilovers to match & went back down to 15... The price we pay for suspension!

 

[mplsdunk]

19.5 combined last tank. All new ignition and 02 sensors and recently cleaned maf. It's all new because I was trying to find a miss. It has tiny 225 tires on it too that the previous owner put on and are almost new. Usually 260-280 miles before the light comes on.

 

[Tek23]

I cleaned my MAF sensor yesterday with cleaner i picked up from Advanced Auto. I also dropped both screws while putting the sensor back. Guess I was all thumbs yesterday…BUT was able to find 4mm x 10mm screws from Home Depot to replace them. Fingers crossed this will help my issue.

 

[lhsoulrebel]

Im lifted with 33s and im still getting 17 in the city and 20+ on the highway. Ive got 294000 on the original motor and tranny.

That's amazing... 5 speed or auto? Don't think I've ever seen those numbers even stock.

 

[Troutsrunner]

That's amazing... 5 speed or auto? Don't think I've ever seen those numbers even stock.

Automatic, idk how people aren't getting those numbers. How heavy are your guys right feet.