Hello all!!

I purchased my first 3rd gen this past Saturday after hunting around for about 7 months. She's in really good shape but does need some reconditioning. I've ordered a bunch of parts to get things going but I've been running into issues..


Issues:

• I cannot find the proper OEM air filter. The two I've purchased look similar, and have the "correct" OEM parts numbers, but are not the same as the current one and do not fit.
• I'm currently, most likely only getting 5 to 10 mpg right now. No codes, what should I do other than filters and plugs? She feels perhaps sluggish but idles and runs fine it would seem.
• The rear brakes hang sometimes, and rarely so the ABS system kicks in when gently coming to a stop... ideas?
• I've read conflicting information on what transmission fluid to use. What is the proper OEM fluid? Toyota ws?

Thanks guys and gals

1) If you're dead set on OEM, I get that. But a filter from Valvoline or a parts store will work just fine. I just sold my beauty with 257k and used Valvoline air filters since new with no issues.
2) Very likely a clogged cat. How does it do on WOT? Egg smell? Sluggish at near redline? I'd replace the fuel filter, air filter, plugs/wires, and go from there. It could be a MAF issue too but doubtful if no codes.
3) Are your axle seals leaking? Occasionally if they or the wheel cylinders leak, it can cause the rear shoes to swell and stick. More than likely, when your brakes were done, the self adjusters weren't set correctly. If it's only after the parking brake is applied, your bell cranks might be rusty.
4) Dexron III is the proper fluid. Valvoline MaxLife ATF works well and I've used it many times with no issues but any Dexron III is perfect for these.

First thing I'd do is clean the MAF Sensor -- it won't necessarily throw a code if it's dirty. It's cheap and easy: cost you $5 for a can of MAF Sensor cleaner, and 10 mins of your time. Search "MAF Sensor Cleaning" on this site, and you'll find what you need.
You still may need plugs, filter(s), etc -- the basics for a tune up. But bad fuel economy, and sluggish performance are classic symptoms of a dirty MAF Sensor.

Well I've been doing OEM filters on my Tacoma just for peace of mind, and I'm especially pampering the 4runner haha.

To be honest I'm a bit nervous about opening her up to 100% since I just got her. I guess I can give it a go. If the cat is clogged do I just need to have it removed? we don't have to worry about emissions where I live, but I also don't want her to sound like a ricer's special project. Haha

I did not think they were leaking but I will check again. Should that even be a possibility with only 123k miles?

I've read slot about maxlife, again since I just got her I'm weary about testing the waters with non-oem fluids.

Yes I've got some MAF cleaner, is the process pretty much the same as the Tacoma? I figure it would be and if so I've got that in the bag! Haha. I plan on performing all of these items on Saturday after getting the new lower ball joints installed and having the AC recharged.

#1) Kind of weird you're ordering the correct air filter part number and it's not fitting in the air filter box. Who are you ordering from? Also, are you sure you're inserting it the right direction?

#2) Like somebody already mentioned, clean the MAF. If you're going to do the spark plugs, replace the wires too. O2 sensor replacement might help but it's interesting you're not throwing any codes. If your cat is clogged, there is a product called Cataclean. I figured if I was ever faced with a clogged cat, I'd try a product like this first before dropping big coin on a new cat. I live in the People's Republic of California so I don't have the option to delete the catalytic converter. https://www.amazon.com/Cataclean-Cat...omotive&sr=1-3

#3) Pull your rear drums off and inspect your brakes. I'm guessing you have leaking rear axle seals and that's why your brakes are hanging up. The gear oil gets into the brakes and causes the brake shoes to swell.

#4) The trans fluid spec for these rigs is Dextron III. Dextron III is no longer being made so you choose something compatible. You could use a Dex/Merc. You could use Mercon V. I just started running this in my rigs: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Dexron lll is still available many places (my Toyota dealer sells NAPA Dexron lll oddly enough) but the more commonly found Dexron Vl is backwards compatible.

You can always buy a Toyota air filter discounted online if you happen to be ordering other parts to defray the shipping....

also, check that the ABS sensors are all seated if its grabbing. I had one that was barely unseated and it was causing the same thing.

1) Never had that problem so I can't help you there.
2) Like others have said clogged cat is possible if bogging down under higher rpm's but idling fine, or it could just be in need of a tune up. It could also need an air/fuel sensor (also referred to as oxygen sensor 1). It would be more helpful if you tracked your mpg for further diagnostic help.
3) Like others have said it could be leaking axle seals or improperly adjusted rear brakes. Very possible given your mileage.
4) I use Dexron VI transmission fluid since it is backwards compatible to Dexron III and full synthetic. Added bonus of Dexron VI is it's manufactured to stricter tolerances/specifications than Dexron III fluids due to Dexron III licensing being expired.

It seems everyone is pointing you in the right direction, but is the intake or exhaust aftermarket, or are there any aftermarket parts? what year?

I ask because my 4runner came with an aftermarket muffler and exhaust that was restricting the airflow and causing a similar sluggish-ness and lower gas mileage.

It's exactly the same as a Tacoma, and a Tundra, and a Sienna, etc. In fact, it wouldn't surprise me if the part was identical for all of them.

Probably not a bad idea to replace the o2 sensors too, it’s only like $45 at rock auto and could increase your mileage

I replaced most of my exhaust recently, my cat was fine so I’m guessing the o2 sensor was responsible for my mpg increase from 13 to 16, yours should be even higher since I’m lifted with 33” mud tires

1) Right? The seller replied back, asked for the year, make, model, trim, etc. "He said yeah it should fit, send me a photo!". I did and he replied "wow I've never seen that before, sorry go ahead we can return it".
What is the correct part number? Just to make sure I do have the right one.

2) Going to clean the MAF tomorrow morning with all of the other items I am taking care of.

3) Will do so when I am working on her tomorrow morning.

4) I will look into those thank you.

Any photos of this? I will add it to the list.

Okay so tomorrow, after warming her up, I'll give her a spirited run or 2 to see what happens. I will check the rear axle in the morning when I am exchanging all of the diff/transfer case fluids.

Okay, so Dexron IV it is then.

I don't think it is, but I will need to check. The headers are rusted to shit and the muffler/cat or whatever looks old and rusted somewhat. I will try to take some photos in the morning and post them.

Thank goodness.

Right? I was expecting her to get at least 18 if not 20 as I always get 21-22 in my 2nd gen taco. I will probably swap the 02 sensors because I am sure after 19 years they may have sensor drift or whatever it is called.


Thanks all

Post that pic here so someone can compare your airbox to theirs.

Poor MPG and no codes I’d say upstream o2 sensor.

But that mileage is extreme. I’d make sure you really don’t have any codes. Is it just no light or have you checked with scanner?

Not really necessary to swap rear o2 sensor for what you’re talking about. I think anyway.

Can check cat with a temp gun. You’ll know if that’s the issue. But that bad o mpg will wreck the cat soon enough, and check the plugs. My bet is front o2.

I just dropped her off to have the front lower ball joints swapped and to have the AC recharged. We are going to summit racing to buy gear oil and then once I get her back I will take the photos. I'll ask the gf to remind me...haha

Just checked her last this morning with torque pro, no codes.
How hot should the cat be?

By chance do you know the OEM numbers for the upstream o2?