Tired of searching... Less power everyday

[4Runnin2000]

So.... For a while now I've had some bad gas mileage. Yeah I know a lot of us do. It has gotten worse and is starting to lose A LOT of power. My intake is getting louder it seems but not going anywhere when I push the gas pedal, It's almost as if it is starving for something. Like I have an anchor behind me digging into the asphalt. Also seems to be downshifting a lot more up the littlest of hills like it can't keep up. Rpms seem to be normal with speed and throttle so I don't think it is transmission related. Fluid still looks good. There have been a couple of tanks where I got 11 mpg and the highest I have gotten the past year is 13 mpg. And that was mainly highway. I can't help but think that the loss of mpg is related to the loss of power. Mpg sucks but not having the power sucks more. I just dont know any keywords to search for anymore. It's a 2000 155k miles. Basically 3" lift and 265/75/16 tires.
New plugs from dealer and ngk blue wires 5k miles ago. Pcv valve and fuel filter at the same time. All oem. All Maintenance is kept up. I'm just at a loss and tired of searching. Anybody have some advice they can throw at me?

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[Difflock]

Clean your throttle body, maf, get a new fuel filter or better yet pump. Spark plugs and coil packs, is it running rich? Lean? Maybe your cat is falling apart


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[Difflock]

I get 350KM to a tank so Idk what that translates too


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[T4R2014]

Check your throttle cables. Spray some silicone spray into them using the straw.

 

[HiLife]

All oem. All Maintenance is kept up.

I'm thinking you might be having a slow a/f o2 sensor. Did you change them out around at 90k miles? Toyota recomend's a change out at that mileage. Are you able to check that o2 sensor with an ohm meter?
Could also be even a dirty fuel injector, (a long shot) strenched out timing belt or timing mark's not lining up.

 

[StreetCreeper]

This is what it was like when the cat clogged up on a crappy Mazda Tribute my wife (then girlfriend) owned at the time.

Probably a long shot, but figured I'd throw it out there.

 

[19963.4lsr5]

This is what it was like when the cat clogged up on a crappy Mazda Tribute my wife (then girlfriend) owned at the time.



Probably a long shot, but figured I'd throw it out there.

I was thinking clogged cat too. Or a going bad pre-cat O2 sensor.

OP, do you have a scanner? And if so does it read live data?

If yes to both is fuel system going closed loop. And what is your LTFT for B1S1 when your driving on a flat road at 45mph and also when it feels doggy.


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[tvpierce]

I would do the following in this order:
1) clean MAF sensor
2) clean throttle body
3) replace fuel filter

Do one at a time, then drive to see if it corrects the drivability issue.

Post back with your results.

 

[4Runnin2000]

Clean your throttle body, maf, get a new fuel filter or better yet pump. Spark plugs and coil packs, is it running rich? Lean? Maybe your cat is falling apart


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Fuel filter is new, new oem MAF has maybe 8k miles. Spark plugs have 5k on them. Not sure about the cat. How would I know if it's falling apart?

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[4Runnin2000]

I'm thinking you might be having a slow a/f o2 sensor. Did you change them out around at 90k miles? Toyota recomend's a change out at that mileage. Are you able to check that o2 sensor with an ohm meter?
Could also be even a dirty fuel injector, (a long shot) strenched out timing belt or timing mark's not lining up.

I replaced my front o2 sensor when I replaced my MAF. So that's fairly new also.

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[4Runnin2000]

I was thinking clogged cat too. Or a going bad pre-cat O2 sensor.

OP, do you have a scanner? And if so does it read live data?

If yes to both is fuel system going closed loop. And what is your LTFT for B1S1 when your driving on a flat road at 45mph and also when it feels doggy.


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I have the torque app that can read live data. Im not really sure how to tell if it is in closed loop or not. I'll open the app and see what kind of data I can read live.

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[Buckaroo]

I like the clogged cat/obstructed exhaust suggestion.

https://www.youtube.com/watch?v=d-jp1IIJVVk

Buckaroo

 

[4Runnin2000]

Cruising at 45 on a flat road. The fuel trim bounced around from - 3 to 3. But I am in closed loop. Am I not supposed to be?

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[MOYotas]

How well does it roll in neutral? My bell cranks on the rear brake drums were rusted and sticking so bad it felt like I was pulling an anchor behind me.

 

[BrianSD_42]

Just throwing this out there. If you put factory sized wheels back on and has the truck dyno'd then you would know the HP and have a better idea of what's actually happening, how much loss etc. I don't know how much that costs but $100 would be my guess.

 

[4Runnin2000]

How well does it roll in neutral? My bell cranks on the rear brake drums were rusted and sticking so bad it felt like I was pulling an anchor behind me.

It rolls pretty normal. The rear brakes are new also. I did them when I replaced my rear axle seals.

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[4Runnin2000]

Just throwing this out there. If you put factory sized wheels back on and has the truck dyno'd then you would know the HP and have a better idea of what's actually happening, how much loss etc. I don't know how much that costs but $100 would be my guess.

I would have to find factory size wheels also. And mount and balance them on factory size tires. All this was happening before my wheels. when I had my 5 stars on. My wheels are still 16s. Just one size bigger on tires. 265/75/16

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[19963.4lsr5]

I keep forgetting this has a MAF sensor. So what I was looking for in the LTFT won't be there.

You can see engine load and your MAF reading. Read both of those at say 50mph on a flat road and compare your numbers to another member who will report what they have. If your cat is clogging your total airflow through the engine will be reduced and it should show up in the MAF reading.

There is also a exhaust back pressure sensor that screws into the front O2 sensor port. But we don't have a thread in sensor so you would need a adapter plate. Plus there isn't any real info out there to say the above X PSI your cat is restricted.

A exhaust shop may be able to tell you. Or you could pull the exhaust apart at the flange after the cat and take a look inside and shine a bright flashlight into the honeycomb.


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[BrianSD_42]

I would have to find factory size wheels also. And mount and balance them on factory size tires. All this was happening before my wheels. when I had my 5 stars on. My wheels are still 16s. Just one size bigger on tires. 265/75/16

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Really if you had a friend with a same year 4runner and stock wheels, that is what I was thinking.

 

[4Runnin2000]

Really if you had a friend with a same year 4runner and stock wheels, that is what I was thinking.

Oh i gotcha. I will keep that in mind if nothing else works!

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