Gas Mileage for 98 4Runner SR5 V6/Tacoma

runner dan
09-05-2005, 04:01 PM
Wondering if anyone knows any methods in getting better mileage out of the 4runner without causing ant threat to the engine.
Heard that a cold intake might help in getting more mileage;
but I thought it would just increase the horsepower.
If anyone has any suggestions, I'm listening.

Brian R.
09-06-2005, 11:32 PM
Well hell, since no one else is posting, I'll give it a shot.

Make sure you are using a fresh air filter. You may consider getting an oil-wetted filter from TRD or AMSOIL. They are very efficient, reusable after cleaning and re-oiling, and somewhat expensive. They are free-flowing compared with efficient paper filters and you can clean them as often as you like. I clean mine every 10k. The TRD filter is oil-wetted cotton and the AMSOIL filter is oil-wetted double layered plastic open cell foam. Don't put any more oil on the element than absolutely necessary.

Some people get additional mileage from opening up the air box (deckplate mod or removing the wheel well elbow from the airbox).

Tweak your AFM (on engines that have them instead of a MAF meter) as shown in:
There is probably an optimum setting for gas mileage.

Your engine may get better mileage with higher octane gas, particularly if you do alot of highway driving. Use higher octane gas for a few tankfuls when you are on a trip, keeping track of the mileage and gas used, and see if that makes any difference. If not, don't waste your money. Say the price of 87 octane is 30 cents cheaper than 89 octane and you get 20% better mileage (from 15 mpg to 18 mpg) with the 89 octane. If the price of gas for the 87 octane is $3.00/gal, then you are paying 10% more per gallon, while saving 20% in gasoline usage. This is a good bargain. If you break even, I would still use the higher octane gas. You have to do the math and the experiment on your truck. At some price, it will be worth it for some percent increase in mileage. In all honesty, you probably won't see a difference in mileage between the octanes, meaning you should use 87 octane. However, it doesn't cost much to try and you should know about it if your truck derives a benefit from the higher octane gas.

Keep an eye on your ignition timing, idle speed, and wheel alignment. A high idle speed will cost you, as well as retarded ignition timing or bad alignment.

Buy road tires. Mud stompers will cost you. I believe that the more noise the tires make on the road, the poorer gas mileage they will give you. Fill the tires with 4-6 more psi than that recommended in your door label. Low tire pressure will cost you. Don't fill the tires above the maximum psi labeled on the tire.

Lowering your truck a couple inches will give you better mileage on the highway.

Off-road driving will cost you. 4WD usage will also cost you, on- or off-road.

Installing manual hubs will make some difference. Each truck will be different in this regard. Manual hubs will keep you from having to rotate the half-shafts and a part of your front differential.

Keep your injectors clean with a fuel additive periodically.

Get any "Check Engine" light problem immediately. Many times you engine will default to a standard condition when a sensor goes bad. It gets you where you're going, but it is far from optimum as far as engine efficiency goes.

Exhaust headers and lower restriction cat converters and mufflers will help your mileage to varying degrees. Buy stuff that you find has helped other 4Runner owners.

I don't believe in cold air intakes. They are a waste of money IMO. Maybe some vehicles have poorly-designed intake systems and are helped by almost any mod. Yours is not one of them.

Fill your transfer case and differentials with 75W90 synthetic gear oil. Leave it in longer to partially offset the additional cost. The thicker the gear oil, the more drag on the truck. Lube your propellor shafts often for the same reason with Moly grease.

Use 5W30 oil in your engine - possibly 0W30 or 5W20. I have heard they work fine, but I have not tried them myself. Those lower viscosity oils will certainly make a difference in your gas mileage.

Maybe I'll make this a sticky - seeing how gas is getting precious. I'll also spread this around to the other truck forums once it gets more mature.

09-27-2005, 02:51 PM
Very through response Brian. The only things I can add are: remove the cross bars on the roof rack (aerodynamics), remove the trailer hitch and other extra weight when you don't need it. I left my trailer hitch on because I park on the street and it acts like an extra bumper. If you have rear drum brakes make sure they are adjusted properly. With the tires off the ground you should be able spin it and it should rotate a half or full turn before the drag of the drum stops it. If it stops immediately then the drum is adjusted to tightly. If their are high spots on the drum then it needs to be turned so that it has an even contact patch with the brake shoes and it drags evenly.

Brian R.
10-25-2005, 09:52 AM
Don't use your Air Conditioner unless you absolutely have to. Your best mileage is when you drive with it off and windows shut. Your worst mileage is driving high speeds with your widows open. When shutting your windows and turning on your A/C is better for mileage than having the windows open depends on the speed and which windows you have open.

If you are on fast roads, try to drive 50-55 mph. This is the speed your torque converter locks up and you get better efficiency out of your drive train. Slower than that and your torque converter unlocks (45 mph) and above that, you get higher wind resistance and cuts into your gas.

02-26-2006, 09:43 AM
Well hell, since no one else is posting, I'll give it a shot.

Buy road tires. Mud stompers will cost you. I believe that the more noise the tires make on the road, the poorer gas mileage they will give you. Fill the tires with 4-6 more psi than that recommended in your door label. Low tire pressure will cost you. Don't fill the tires above the maximum psi labeled on the tire.

Just thought I would add a few details. On running higher tire pressures keep in mind that the cars handling will be affected and if there is a specified difference between the front and rear it should be kept proportionately the same. Especially in the front you will notice the steering becomes alot more squirrely and spin outs and roll overs may be a little easier to acheive.

Driving habits can save you alot of mileage. Start coasting earlier for stops; don't charge up to stop signs and brake hard! It is lots of wasted energy and your mileage will suffer. On the flip side don't charge out of the gate like a horse race; accelerate easy and smoothly. In other words start driving like an old person, you will get fewer tickets. If you find it hard to do because you are in a hurry to get to work just leave 15 min early and you can conserve fuel while lowering your stress level and impressing the boss by actually showing up for work before start time!

Put your auto in neutral at the stops; the engine won't have to work against the torque converter.

I don't drive with my tailgate down because I feel that someone might hit it and it would cost more to replace than my bumper.
Thats all I can add.
Hope it helps.

Brian R.
06-04-2006, 09:22 PM
Although I don't have any data to back this up, I bet that a pick-up gets alot better mileage if you have a bed cover on it or a light-weight shell to increase the aerodynamics at highway speeds.

08-13-2006, 03:00 PM
Believe or not, the tv show Mythbusters did a show on fuel economy and having your tailgate up and down. Turns out that having the gate up actually results in better fuel economy.

Brian R.
08-13-2006, 04:14 PM
I'll bet a shortbed and longbed pick-up will get different results, and at different speeds. Better try it yourself on your truck and come to your own conclusions.

Brian R.
08-13-2006, 04:19 PM
Also see the other sticky post:

09-12-2007, 02:17 PM
I am also not a big fan of cold air intakes. I put one on my 1997 chevrolet tahoe. To get my money back for the intake from gas milage, I would have to drive about 200,000 miles. The intake cost over $500 for the kit, and the gas milage difference was very minimal. I did however notice a slight horsepower increase, but I wasn't blowing any doors off at the red lights.

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