Just looking for ideas on why I am still only getting 10mpg town and 15mpg highway with my 4runner. Check the list below for all the stuff I've tried. None of it has helped (but at least its good maintenance). Anyway, just wondering if you guys can think of anything I've overlooked.

Vehicle Specs: 95 4Runner, 3.0L, A340H (auto tranny), 4.88 gears (stock), 31X10.5 tires, Downey coils in back.

What I've tried:

1) Semi-Synth lube everywhere (oil, tranny, T-case, front bearings, difs, driveshafts, balljoints)

2) New plugs, cap, fuel filter, air filter, timing belt, drive belts, PCV

3) Timing at 10 deg. BTDC

4) Cleaned out intake manifold, and TB

5) 2 cans Berryman FI cleaner over the last year. One can of motor flush during last oil change

6) 93 octane (helps a little)

7) Swiss cheese airbox.

8) high flow muffler w/ 2.25" pipe from cat back

9) Checked EGR and modulator (both OK). Checked cat (not plugged)

10) Tires at 45 psi.

11) Very easy driving (i.e. no lead foot, slow accelerations, N at stop lights, etc).

12) All wheels rotate fine by hand when not engaged (i.e. no binding or rubbing of brake pads)

13) Warn hubs up front

 

Just one thing that i know of tha tyou forgot to replace....

your 3.SLOW...



sorry, but i think that's about as good as it gets with a 2nd gen.

 

I did not see O2 sensor replacement on that list.

 

Good thinking. My bad that I forgot to list that one. It was one of the first things I replaced when I got the 4Runner. OT, the O2 sensor was completely free. The owners manual said take the vehicle in at 80k and get a free new O2 sensor. The dealer didn't believe me at first, but sure enough, the sensor and labor were both covered by Toyota . I think they only did that for the 95's (at least that's what the dealer later told me) but I'm not entirely sure. In anycase, plase keep the suggestions coming


LOL. I do miss my old S10's 4.3L Vortec. If only I could have magically placed it in my 4runner. And I agree that a 150hp motor being used to move a 4,500 lb vehicle is a major part of the problem.

 

Usually a bad O2 sensor triggers a check engine light.

Check your AFM. That caused my poor city mileage.

 

Here's a question for you. Do you drive with the windows up or down. Windows down cause alot of drag believe it or not, and will cause poorer mpg than driving with the AC cranked up.

Also have you adjusted your TPS?

 

Windows rolled up, down, with A/C on, with A/C off, with some part-time wheelin in there; I can't say I've EVER seen a noticable difference in my gas milage while I've done any of the above combinations. But my experiences is with a 96' V6, so I don't know.

 

Good thought. I have made sure the flapper valve (or whatever its called) moves freely plus sprayed some lube on it. It does rattle a bit, but seems to work OK.

As for the windows, another good thought. They are down around town (speeds under 40mph) and up on the highway (with AC on). As for the TPS, I have had it apart but haven't really adjusted it (didn't know that was possible). I will have to look into it. Thx.

 

I see you cleaned out the intake manifold & TB, do you have a MAF as well? Is that cleaned?

On a side-note, my mileage dropped between 1 - 2 mpg when I had my muffler installed. Don't know if it was just coincidence or what but thought I'd mention it. My mileage has improved since I cleaned my MAF and TB a few days ago, as well as put in a paper filter (so I could remove my Amsoil one for cleaning).

 

No, you have to go through the electrical tests outlined in the factory service manual (I think chiltons or haynes has it too). Becareful because it's real easy to break the afm and a new one is around $700.

 

While I agree that having the windows rolled up is more aerodynamic, I doubt on a vehicle shaped like a brick it would matter much. On a side note, back in highschool I was in my friend's geo metro, loaded with 4 guys. When we are merging on the freeway he says, "roll the windows up, we'll go faster." We couldn't stop laughing.

 

and

So you checked your afm and it was OK but cleaning out the internals helped your mileage OR you replaced the entire afm b/c you found out it was bad? Just wondering b/c even if I test mine and it is bad, $700 could buy ALOT of gas . Maybe more than I would gain by replacing the afm (at least in the short term of a few years or so).

Again, though, great input. The more the better!

 

This all happened back before I knew about message boards so I just took it into the dealer and they told my me afm was bad. Cost me $700. Do a search and you'll find some more info on how to do the electrical tests on the afm. I think you have to check the resistances.

Sure you can buy a lot of gas with $700, but think about what is happening. If you're using more gas then you're probably running rich. This could lead to carbon deposits, O2 sensor problems, cat problems, emissions problems, etc.

 

Are you sure that you have 4.88 gears? I've read that only 4 cylinder autos with 31" tires came stock with 4.88's, and v6's with 31" tires *usually* came with 4.56's.

Granted, I have a 3rd gen and know nothing about 3.0's, but the stuff I reference was from this site.

 

LOL. I got the gear code off the door jam and was CONVINCED it was wrong. No way I could have 4.88 gears with a 3.0. I jacked up the back and counted tire revolutions per driveshaft revolutions. It was close to 2.5:1 for a single tire (meaning 5:1 for both tires), but I still wasn't convinced. I ended up removing the rear third and counting ring and pinion teeth so I would know. Sure enough, I have 4.88 gears . Turns out its all part of a factory tow package. Interestingly, the reccommended tires size for these gears is 28" on the door jam. Must be for that much more low end power. I've got 31s on now and will probably up them to 32s in the future. 33s? maybe, but that may be more low end power loss than my runner can afford. Also, a little more info, I've heard that the thirds from 3.0Ls with 4.88 gears are not swapable with other thirds. Haven't tried this though, so not sure if its true.

Finally, here is a picture of the model info sticker I snapped back when I was trying to figure it all out:

 

Cebby and I have 4.88s. It's not too uncommon.

 

Kewl! I learn something new every day around here.

 

did you check the flux capacitor????

 

buy an echo

 

:


It seems like you've covered all the bases to improve you mileage, I would try cleaning your MAF sensor real good and hope for the best. How are you calculating you MPG? Are you sure you are doing it right? I'm not bashing you at all, but sometimes people don't really know how to calculate their mileage(I didn't in the beginning).