YotaND

So, I am making a 4k mile trip next month in my 92 runner. Right now it only gets about 12mpg. I figured on this trip alone for every 3mpg more I can get I will save $200 and an additional $200 every 3 months with my current driving habits. So, what can I do to get that extra mileage? The cheaper the better but I’m open to anything.

I have considered headers but can’t find any good info or prices online and I have no idea how much more power and mileage I will get. I have also thought about getting a new cat or removing my cat all together. I think my original one may be clogged. What about hubs, k&n FIPK, O2 sensors or anything else I haven’t thought about?

I guess the question is what are my options and what will give me the most bang for the $$? There is so much involved in a vehicles efficiency I don’t know where to start.

regularguy412

Run the highest tire pressure you can without causing premature wear in the center of the tread. Also, make sure you do a complete tune-up: plugs, dist cap and rotor,, check the base engine timing. Check to see if your plug wires are within spec. Clean the Throttle Body ( use throttle body cleaner, not 'carb' cleaner). Clean and lube the AFM door ( be very careful when working on the AFM -- DO NOT remove the screws that hold the AFM connector to the AFM body -- there's a couple of little clips on the sides of the connector that allows the plug to come off). Change the oil. Try not to haul any more extra weight than is absolutely necessary. Accelerate like there is an egg between your foot and the accelerator.

Mike in AR

Paul H.

If you are only getting 12mpg highway then something is definitely wrong. get a tuneup( plugs, wires and check your timing), you may have a bad O2 sensor also. You should be getting at least 18 mpg if you drive light footed.
And forget about the K&N, just put an OEM filter in there.

AH64ID

change to synthtic fluid in enging, tranny, xcase, diffs... and add hubs to the front end. This will reduce drag and wear.

What size tires are you running? What cam stock?

Elton

my 91 got atleast 18mpg

ChickenLover

That's what I get. Up to 20 on the highway.

tc

x2 for tire pressure and timing

navyredneck

My 94 v6 4WD 4runner with 3vze gets 16 mpg around town and 17 mpg on freeway (and about the same in the woods in 4wd).

Of course, I never use the AC unless I'm going faster than 45 mph more than a few minutes. I also replaced my front hubs with toyota hubs (from ebay/junkyard) that cost me overall around $95 after I rebuilt them with all new gaskets and bolts. As far as I have noticed so far it looks like the hubs are getting me an additional 1 mpg or so. In fact, the front end even sounds different when I start out now.

Oh, and think long and hard before putting synthetic oil into an older engine that hasn't used it before. It will clean up your oil seals resulting in engine seal leaks. Trust me, I've done it...

YotaND

I am running 31 10.5 tires. I just put in new plugs, wires distributor cap and rotor. However I did not use the NGK plugs. I am running the Bosch platinums. I bought the plugs before I read all the post to use only NGKs. My idle smoothed out nicely after the ignition tune up but my mpg stayed the same. I have some used injectors coming that I bought from eBay and plan to send them off to be ultrasonically cleaned. I can't just take out the ones that are in there now to be cleaned because it’s a DD. I have also changed the fuel filter and cleaned the throttle body and adjusted the TPS to spec.

I have a stock cam and I advanced my timing to 12 BTDC hoping it would help.

F0RSAKEN

Something is really wrong with your truck. I just made a trip from Seattle to eastern Oregon two weeks ago. Averaged about 75-80mph with about 100lbs of cargo and two people in veh (me and passenger), over the pass basically floored, had cruise on the rest of the way and I averaged 19.8mph there. I use premium because I usually get about ~20 miles more per tank, and its better for the vehicle (argue away, it will fall on deaf ears). My return trip I got about 2mpg worse due to my step dad filling my T4R with the lowest grade fuel (my belief).

Anyway, as everyone said, full tune-up, but get a new fuel filter too. I did all of this the week I bought my truck.

AH64ID

This is not true, on average.

I have added it to rigs at 150K, with no leaks. Synthetic doesnt create leaks, but it can make current leaks larger. Therfore if you have a small leak now there is a change it will get a little bigger.

I would think you have a clogged injector or something to that effect. Also if your stock tires were 225's do you account for the approx 9% difference? That would bring 12mpg up to 13, but still seems low.

I would also check to ensure that your e-brake is releasing all the way.

YotaND

How would I check that? There seems to be a little play in the line when I pulled on it at the T the last time I was under the runner. There isn't a lot of play but I can pull on it sideways about 1" or so.

AH64ID

See how easily the rear wheels turn when if you jack one up.... If the handle seems to engauge right away it may be too tight.... You would proballly also smell hot breaks if it was on way too tight, but it could be just a little tight.

TNRabbit

I've found that crappy mileage on an otherwise good-running truck is USUALLY causes by the O2 sensor. Here's a suggestion: crack it loose & spray really well with throttle body cleaner, then re-install & see how it does for a tank. If no improvement, I'd replace it WITH AN OEM or other Japanese make. DO NOT purchase the cheap, non-Japanese (Denso or NGK) O2 sensor; you will be wasting your time & money.

YotaND

I won't be able to check the brake until I get my jack on fathers day but I am going to try to take a look at the O2 sensor. I have the bolts soaking in WD-40 right now but I don't know if it is going to work. This thing is rusted so bad I'm not sure I will be able to get it off. Is there any tricks to it?

AH64ID

I had to use vice grips to get mine off, the nuts were shot but the stubs were fine.

rentedmule

O2 sensor made a huge diff for my 3.0, but mine was gone to the point of turning the engine light on. i probably gained close to 5 mpg when I fixed it. Definately stay away from the FIPK. If you're going to go for a K+N get a drop in filter and do the ISR mod (there's a tech write-up in the performance mods section). You'll save a pile of money and get the same minor performance/milage gains as the FIPK.

YotaND

What should I use to clean and lube the AFM? I’m not to sure where to lube but I’m sure once I get it out I can figure it out. Also, why does my AFM sound like a Geiger counter? I know it is not the reed valve I'm hearing or any other part of the EGR system. I'm not sure if the sound originates from the AFM but that is where I can hear it. It is audible when the engine is running and very loud when I unclamp and open up the air box. I pulled the vacuum line from the left valve cover to the air hose and listened. I could not hear the noise there but it is hard to hear anything over the sound of suction.

Will too much oil affect my mpg? When I drove it off the lot the day I bought it the oil was over serviced. There is an oil leak that drips a few drops a min after it has been running. I’m not sure if it is caused by the overfilling or if the overfilling was to compensate for the leak.

<==E[/////////////////]F=======S========

This is about how high it is. The S is what my dipstick shows for oil level. What do you think?

Chuki

This is true, synthetic wont create leaks, just makes them evident... Also synthetics have a higher amount of detergents so if you have a highmileage engine, as in 150k+ it is recommend not to change to synthetic (amsoil rep even told me this, although its not on the bottle ) If you have a lot of buildup it could be creating a "false seal" meaning once its washed/cleaned up you'll have a leak. If you have any sign of any kind of seapage (check the front of your engine) like oil may slightly seep through but not drip, synthetic will fly on through.

What I did to get more mileage out of my 5speed with 3.0 was, manual hubs, k&n, and put synthetic in all your drivetrain, in the motor it wont make any diffrence if it does its only gonna be in numbers, with synthetic vs. crude in the engine I bet you'd be like to see .1 mpg more... Where synthetic really helps in gas mileage is in the drivetrain.

oly884

To be honest, the best thing you can do to get better mileage is just go slower.

I take a different route to work now-a-days where i don't go above 60 mph and i'm getting 20-22 mpg with the V-6. When i'd take the interstate at 80 mph i'd get 16-17 mpg. Nothing was different about my driving except the speed.