BMWToyotaMan

Hey guy, I have a completely stock 98 4runner limited 4x4 (purchased back in june). It has 128,000 miles on it. I was getting around 15mpg with city driving and a small amount of highway driving before the tune up. I wanted to get better and I knew the 4runner needed a tune up anyways. I replaced the air filter, fuel filter, spark plugs, plug wires, 02 sensors and I did an oil change. I filled up my tank the other day and got 13.6mpg, I drove like a grandmother the whole time.

What else should I be doing? I am going to get some fuel injector cleaner but im running out of ideas.

Any help would be great.

Thanks,
Jeff

Ric

id try some seafoam, and see if that helps any

Brisk

my runner is also horrible for gas milage.. and I've got the 2.7L 4 banger.

I recently did a tune up as well, the usual.. plugs, wires, air filter, and changed the oil and filter. I found I still had the original plugs in her at 174,xxx kms! Seems to idle smoother and gets a bit better gas milage, but not much. I'm getting about 500kms per tank of petro.

I too am curious to see what else can be done for a bit better milage.. short/ram/cold air intake, better exhaust?

Elton

deckplate mod isr mod trueflow filter and a magnaflow muffler ... mine gets about 19mpg i think thats cause i have a 5spd

AH64ID

First, how are you calculating mileage?

How old are the diff/xcase/tranny fluids? If old or you dont know replace them with Amsoil, they last longer and get better mileage

Check tire pressure.

What size tires are you running? It says compleatly stock, but upgrading from say 265/70/16 to 265/75/16 will look stock, but thats a 5% larger tire.

Remember any mods you do for mileage usually take a LONG time to pay off at maybe .5-2 mpg gains.

rcars4life

I recently did the deckplate/isr/trueflow mod and i am annoyed by my loss of mileage. I am not sure if it is because my filter is dirty from offroading with the deckplate open or what, I capped the dp and got the same mileage so I'm not sure. Next is to clean the filter w/closed dp then open dp guess we'll see. (I was getting ~20 mpg, now i get ~15.5)

For me I notice a huge difference in mileage with my tire pressure, I am on stock wheels/tires but still. Also I'm sure this crappy winter gas has something to do with all the loss in mpg threads.

sorry not to hijack-when you clean a trueflow can you just rinse it or do I have to get the recharge kit thanks!

misterzee

hmmm, have you done any mods, like big change in tire size?
Check for plugged CAT in the exhaust?

Just so you know its possible, I'm driving a 97 4runner LTD, V6 Auto 4x4 stock, with stock 16" BFG Long Trails (hate those things) and I get a rock steady 21 city 24 highway. I log every fill up and maintenance item.

BMWToyotaMan

I have the stock 265 70 16s. The trans fluid looked fresh when I checked it out, I havent looked in the rear diff or transfer case. My motor ran much better after all the things I did but I dont understand why I lost mileage from before the tune up. I will try some seafoam and see how that does.

Jeff

BMWToyotaMan

wheres the best place to put sea foam in the engine?

CJM

Put the seafoam right into the intake..

Honestly did you ever think it could be because, well its a heavy truck? I have a T100 and its a bit heavier than a runner of that gen and it gets 16-17mpg city.

Lets not forget the front hubs, automatic hubs are always on, reduces mpg.

Last, your sure your calculating it right?

BMWToyotaMan

well as you said your truck is heavier and your getting 16-17mpg, I got 13.6 on my last tank. I record what mileage is at everytime I fill up and divide that number by the amount of gas used.

CJM

Well are you doing it like this: total # of miles on trip odometer (Divided by) total gallons filled up?

Anyway it could be the fact that your doing all city driving and the winter grades of fuel round now. Just for reference I went from 16ish to 14.7 with the winter grades.

Or it could be the combination of new parts, who makes the spark plugs and air filter? They could be causing problems, I would only use NGK plugs and purolator or amisol air filters, same goes for oil filters. Then there is the fact the oil you used may not be what your engine likes.

SLC97SR5

Did you pull the EFI fuse or Negative cable after all the new parts? You should do this anytime you change something on the vehicle. It gives the ECU a clean slate to derive settings from. If you did do this you may be getting worse mileage because the ECU is "learning" what it's like to have new/different parts. Eventually the ECU will get to where it want's to be, pulling the fuse or Batt just gets it there faster.

BMWToyotaMan

Yes the negative calbe was removed when I did all that.

I will let you guys know what I get on this tank.

AH64ID

Have you checked your tire pressure? Its winter, cooler air means lower psi if you dont adjust them....

Elton

this vaccum line works best

gapboi210

I have a can of Sea Foam sitting on the shelf. How much do I pour in there? And how do I do it? I have a rough idle and bad mileage too.

nickr9287

how do you start a new thread i have a lot of questions about my 91 4runner

Elton

read the bottle and search around

Elton

search first and if you can find your answers ......https://www.yotatech.com/newthread.p...ewthread&f=120