lectric80

Ok, so I know they are underpowered and don't get the best gas mileage out there, but my 94 4Runner shouldn't be getting 16.5. So, I'm making a list of the things I'm going to do to try to improve it, most from searches here, but please let me know if there are any things I miss.

Right now my drive is 85-90% highway/freeway. I drive typically about 65-70 the entire way, use my cruise, take off gently from a stop and try not to mash the skinny pedal.

So, the things I have planned are as follows:

Clean the throttle body (this needs to be done anyway as the throttle is sticky and doesn't close all the way, current idle when warm is around 1200)
Remove the turbulence box from the air intake (thanks to the sticky)
Replace plugs, wires, cap and rotor
Run a couple of tanks of injector cleaner
Install manual hubs (this one may be a while)
Replace air filter
Possibly install cold air intake setup


Ok, so what else works? I would ideally like to see it closer to 20, and honestly the 16.5 is probably being generous since my speedo is off and reads higher than I'm actually driving. Real MPG is probably around 14-15. The truck hasn't been lifted, twisted or modified, and is as close to stock as any I have seen with the exception of having 31's in place of the original 225's. Or am I just doomed until I can rebuild the engine and add a set of RV cams?

4mydogs

I've had my '95 since 1997 and have put 200K miles on it, and I never got 20 mpg. Closest I ever came was 18, and more typically get 15-17 in mixed driving local/hwy.

xfactor203

16.5 isn't terrible for a 3vze 4runner, but they can do a little better. I've averaged 17-18 city 19-20 highway in mine up until this year (it just dropped off to about where yours is this winter). The best I've ever gotten on the highway is 22. All I've ever done is kept it tuned up, changed air filters regularly, run relative high tire pressure (35-38 psi), and not driven too fast. I also run 31's.

RJR

Auto or manual? My 4runner with the manual gets about 18 in mixed driving, about 19-20 in optimum conditions which is 45-50 mph, and drops off to about 17 at 70 mph and 16 at 75 mph. Seems like folks with the auto get about 2-3 mpg less than the manuals.

Adding the manual hubs was barely noticeable. Maybe .5 mpg. I added them because of the locker up front, not for mileage.

Sturmcrow

Did you change the speedo gear when you put the bigger tires on? If not, I am pretty sure that you are getting better MPG than 16.5, not worse. The odometer will be underestimating the distance that you traveled on a tank of fuel.

scope103

That's your "problem." If you slow down to 61mph you'll pick up at least 10%, where ever you're starting from. Of course, if you're in a hurry, the "dollars per hour" isn't that great. But it's a much better return than any of the modifications you've cited.

I generally get 20mpg highway driving, and I've gotten it as high as 22 gas-station to gas-station on relatively level road. With an Automatic transmission.

Driving in the right lane all the time is not for everyone, but if saving gas is what you want to do, it works.

MaK92-4RnR

I've never gotten anything better than 18 in a 3vz. my 4runner is SAS'd, on 37s military tires, geared and a 5 speed and still manages to pull about 16-17. 18 is really only on a long trip and generally doing 60-65 mph the whole way.

Gamefreakgc

I've done a lot of research on these and done most of them (plus some) so I listed them in order of best MPG gains to worst. I improved my MPG's to 13.5 mixed to up to 18 MPG's mixed for a time (then I did power mods and lowered it ).

1. Cat-back exhaust system with Magnaflow/Flowmaster exhaust and upsize the piping 1/4 inch. Raised my MPG's roughly 20%, you won't regret it. Most shops will do it for under $300. Gains some nice HP as well.

2. Running 91 octane or 93 octane fuel. I know this one seems odd, but I gained a full MPG from running it. It offsets the cost enough that I basically break even (the extra 20 cents a gallon offsets the 1 mpg gain). But I run cleaner, more efficient gas!

3 or 6. Cold air intake: might boost your MPG's or lower them! In my case, the extra air coming in needed extra fuel so it knocked it down. The power is nice though.

4. Maintenance items: clean throttle body, wires, cap, rotor, plugs. Might have some lost performance here but seeing that you are already getting 16 or so, probably not.

5. Replace Air Filter. Might have gains here if your filter is old and clogged. You could try putting in a K&N or Amsoil filter (some say the Amsoil ones filter better but still allow more airflow). If you off road a lot then don't put in anything but a paper filter.

6. Seafoam/Amsoil Power Foam. If you think your truck is REALLY dirty inside the engine, run it through your brake booster or better yet, through the throttle body using seafoam spray/Amsoil power foam using the seafoam spray hose. Works well to clean things out and allows more air in, potentially raising MPG's. There's a recent thread about this

7. Correct Engine Oil - These trucks use 5W30 oil. Anything heavier is unnecessary unless you live far up north and will potentially drop you MPG's.

???. Engine Flush. This one's on my to-do list. Supposedly it increases the engine's efficiency by removing buildups in the engine oil. Unconfirmed.

Negligible items:

Manual hubs - Unless you want these for offroading purposes, it will do nothing for your MPG's. The few parts it will no longer use doesn't justify the work involved and there's little friction on those parts.

Fuel Injector Cleaners - unless you know you've got a mucky, dirty engine and clogged injectors this one won't do much either. I only run them when I've ran through some Seafoam and concerned that my spark plugs are dirty. Doesn't hurt though, and at $4 a bottle won't hurt the wallet.

xfactor203

Well! Haven't done this yet and it so happens new cat-back is on the agenda this year anyway due to rust. Hopefully I see similar benefits.

RJR

Thanks for that list, Gamefreakgc. That's a good compendium of ideas all in one place. I too have found that running mid-grade gasoline picks up enough mileage to justify the extra cost, and gives a bit of a power boost as well. The theory behind that, I think, is that the ECU advances timing until the onset of knocking. With higher grade fuel it can advance the timing further, improving power and efficiency.

Gamefreakgc

Exactly. You can also run advanced base timing as well if you want up to 15 degrees, to eek out a little more power. I can't though, my old engine won't have it.

lectric80

Thanks for all the information. It is a 5 speed and I know the mph is reading high so the odometer is running up more miles than I actually travel. I didn't change the tire size, it was done by po. Good to know on manual hubs. I will work with all of this and report back.

cobolt23

you could (this hurts to say) go back to the 225's, the smaller rotating mass will help some. If this is an on road only truck, get passanger tires, they have less rolling resistance then a/t. or you can get to sets... 31's for off road and 225's for on road. It's a thought...?

bone collector

I get 17 city and 19 highway in my 3vze. the 5 speed helps a lot. I could do better in the fuel economy department but I drag race from light to light and treat every corner like it is the final corner in the Baja 1000.... lol. and yes I get that mpg on my 33s

lectric80

Typing on my phone sucks. I do know it is going to need a muffler anyway, so a complete cat back isn't a huge deal to do. I'm hoping to throw a new cat on it at the same time, who knows if it has ever been changed. I just picked this truck up last week, so there is a lot still to do to get it where I think I can get it with my normal drive.

lectric80

Ok, I didn't get to the throttle body this weekend, but I do know that the throttle cable is not the cause of my sticky throttle, it is most definitely the throttle body itself. I have the cleaner, just didn't have time this weekend to work on it. I'm also going to check the air filter, since I don't know it's current condition. Oil change is also on the agenda, I don't know when it was last changed, and I always run 5w30 in my vehicles.

I will be putting 91 in my next tank to see what, if any, difference it makes in MPG. I will be happy to report back.

After that I will be picking up new wires, plugs, cap and rotor. I don't know the age on these parts, so changing them can't really hurt anything.

I'm going to try to get the exhaust done next month, it will take me that much time just to ensure I have the money due to things beyond my control.

Beyond that, I plan to drain and refill the trans, transfer, front and rear diffs with fresh GL-4. I don't have any way of knowing if they have ever been done, but after bleeding the clutch, it still feels like the trans doesn't shift as smooth as it should. It is much better, but still feels a little "sticky" between gears. It feels less smooth than the 90 pickup I have been driving for the last couple of years.

I will also check out Seafoam to add it in, with 245k there is no telling how much carbon and other buildup is in the engine.

chefdave

Hi lectric
if doing trans oil try a passive flush. drain a litre of oil then add a litre of fresh oil. after 200 miles do the same again until oil turns red. Dont use seafoam strsight off as all the gunk in auto box will be removed in one go and could auto to blow up. i use dexron 6 in my auto box and what a difference. smooth chsnges from start up in sub zero temps and stable in high amibent temps under heavy load.

Gevo

From my few miles on my rebuilt engine and transmission (950 miles now), I find the speed making a huge difference in mpg's. The 3vze is not efficient at 75mph. My average so far has been 14mpg. Every tank I fill up I drive a different 'way', (heavier acceleration, slower or faster on freeways, etc) to get a feel for her overall abilities and how it likes to be driven.
I feel that there is something that can give me a little bit more MPG's, but I haven't figure what. I have all new tune up parts and new cat, new muffler and new sensors in the fuel related systems. From what I' have been reading some people say that after the engine is broken in it gets better mileage. I'll see soon enough. Otherwise, 14mpg is not great, but I can live with it. My tires are on road regular size tires that are inflated to proper spec.

I think my car has more rolling resistance than it should, popping it into neutral as I do on my manual Audi A4 in the same areas, it does not roll nearly as far as the A4 does. So that's something you may want to look at. I worked on the front left wheel and for sure the breaks need some fine tuning to minimize the resistance.

dropzone

iTrader: (6)

get a GPS to track a tank accurately.
seems to me if you are getting over 16mpg you are doing good..

93Xtra-Cab

During the summer, I get 22-23 in my pickup, about 18-19 during the winter. 0% freeway, 100% backroads.

My truck is a 5 speed and has a cheap-o cold air intake, magnaflow muffler, cat delete, 32" tires, 4.30 gears, and I run 10w-30 oil and 87 octane fuel.

Try driving slower on the freeway. 65-70 is not an efficient speed for these trucks. 55 mph +/- is a much better speed for fuel economy. That's why I stopped driving my truck on the freeway..because I can not drive 55...LOL