chahci

I just bought a 1991 4runner with 3.0 and auto trans with 132,000 miles.

HG done at the dealer in 2001.
ALL STOCK except:
I've done:
Intake Silencer removel.
Denso O2 sensor.
K&N air filter.
Free flow Cat.

It codes the TPS so I checked that the TPS is closing all the way but may not have put it back on in the right position.

The auto trans the PO had rebuilt at Aamco Transmition last year but it seams like it pulls alot of RPMs just crusing around town.
It shifts fine into all gears and if I let off the gas a little I think the torque converter locks up.
If Im going like 35mph and let off the pedal a little the RPMs will drope under 2000 but if I give it a little gas to maintain speed it kicks down and pulls 2500 + RPMs.

Please help! I would like to get better than 9 MPGs in town.

Thanks.
Kevin

tc

What size tires and gears? (Please search to see how to determine your gear ratio)

Is the ECT in "normal" or "sport".

Unfortunately, I have to say that 9 MPG is not out of the normal distribution for auto 3.0 4Runners ....

chahci

Also when I got the 4runner it was only getting 7MPGs in town so thats why I started serching the web, found this website and started doing the mods.

I sold my 91 Toy pick up to buy this 4runner because I needed more room. The pick up was getting over 16 MPGs in town.

If I can't get close to 15 MPGs in town with the 3.0 I might as well put a V8 in it.

Kevin.

tc

3.0 = 4cyl power with V8 mileage ... especially in a heavy 4Runner ...

chahci

31" tires
Stock gears
Tried sport for a coouple tanks, doesn't seam to make a differnce in MPGs.

Kevin

iamsuperbleeder

lmao, I like that...

89silverpu

If you're in CA what o2 sensor did you replace?? The pre cat or post cat? If you're in CA and you replaced the post cat thats not going to do anything...you need to replace the pre cat...but if you're not in CA nevermind lol...

GREG337

Try hitting everything with a grease gun. Mine wasn't as bad but when I would let off the gas it would instantly drop speed even down hill.

olharleyman

try replaceing
fuel filter ,02 ,cap ,rotor ,plugs and wires ,air filter,seafoam the engine and see where you end up

312necro213

With what ohharleyman just stated I bet you gain anywhere from 2 to 5 mpg.

chahci

I live in Iowa so it could be gas.
The 4runner coast fine but I'll grease every zert I can find.
I poured SeaFoam down the booster tube (my wife thought the Runner blew up)
I'll do the rest of the tune up ohharleyman said and post my results after the nest tank of gas.

Thanks Guys.
Kevin

chahci

Also can anyone piont me in the right direction for auto trany info.
I think this could be part of the problem as it seams to kick down to easy.

My Toy pick up had a 5 speed manual and I could keep it under 2000 RPMs in town.

Thanks.
Kevin

mr_schuster

If you are honestly getting 9MPG that rig should be dumping fuel or black smoke out the tailpipe. (IMO)

Diagnose the TPS first, if its way out it will give the computer bad input, making it seem that you foot is in a certain position on the gas pedal.

Check you air pressure too.. Thats a killer of fuel economy.

chahci

No smoke.
When my fuel light comes on I put 10 gallons of gas in and usualy get about 90 miles when the light comes back on.

What if I unhook my kick down cable from the throtle body? Will this keep it from kicking down when I lightly press the pedal and can this cause any damage.

Also what can I add to the trany fluid to help.

Thanks.
Kevin

chahci

Maybe I should video my tach and speedo while driveing to give a little better idea of what im seeing.

Kevin

Luvmeye22re

Yeah but 9 mpg? In my 90 pickup ADD doing highway and normal around town (Evergreen CO) 3.0 manual I'd get damn near 15-20 most of the time (in the middle of that range usually), I can't see an auto trans causing it to be that much worse The 3.0 is not a powerhouse nor is it the most efficient of engines but it's not a 9mpg gas hog. Something is wrong.

I don't think there is any liquid that you can add to the trans. fluid in this situation. Is the truck sluggish or running ok?

24Runna

Heres what I recommend, as I was getting near what you were saying.

-1/2 can in the brake booster line (2 treatments recommended way apart). 2 - 3 in the tank. $25
-Replace plugs with NGK G-Power, or V-Power $20
-Replace wires with either stock or NGK ($36)
-Replace cap & rotor with stock $25
-Change out all fluids. Get 10W-30 Mobil1 High Mileage, and change out the rear diff and front diff with Mobil1 75W-90. Also drain and fill, or do a flush on the trans (15 qts.)
-Check air pressure in the tires
-Change ADD to manual hubs $20 - $200
-When accelerating, don't go past 2.75k RPM (It's a little slower, but it helps)

That all should net you a damn good amount of MPG. I used to get piss poor, but now on the highway in winter weather and winter gas I get 20 MPG.

Another thing, do post a video of what you are saying. I THINK I might know what you are talking about, but I'm not sure.

tc

Going from a manual tranny truck to an auto tranny 4Runner could EASILY explain you going from 15-20 down to 10-15.

I didn't say 9 was NORMAL, I said it wasn't out of the normal range - it's certainly on the low side, though.

Kiwipushrod

X2

Thanks, Kiwi

rowdy235

Personally I would say that when you combine the underpowered, somewhat unefficient engine (see tc's remark), the heavy 4runner, and the power drain of the automatic tranny, its not that hard to believe the drop from 15-20 to 9.

PS if you're transmission is messed up, every automatic I have every drove is too.

I hate to tell ya but IMO there's not much you can do except attempt to drive more efficiently.