2000 Runner SR5- bogging down

BORGS8

MEMBER
2000 TOYOTA 4RUNNER

2000 Toyota 4Runner SR5 4WD, V-6, 140K miles- When it starts out, up until about 2000 RPM, it really bogs down almost to the point of stalling. Never has stalled though. Pull over and let it idle for about 10 seconds, or rev engine a few times while stopped until I get RPMs over 3000, engine then runs fine for duration. Switching to ECT mode sometimes helps. Shut it off for awhile, turn it back on, might do it again, but not always. I doesn't do this all the time, about 4 times a week. Truck works fine over 3000 RPMs. Last night, when it did it, it actually made a few loud popping sounds. First time it has done that. Today, worked fine all day. No check engine light indicator. Had an oxygen sensor replaced about 2 months ago, seems to be doing it since that time. Fuel pump, coils, dist. Cap? At a loss. Thanks in advance.

11 Replies

FISHERMAN

MECHANIC
938 POSTS

Hello!

Well, start with a good tune-up, spark plugs, distributor cap rotor, wires, gas filter (important) air filter.

Check and clean also: EGR and IAC valve.

If possible check the fuel pressure on the pump.

That should help a lot on your engine performance!

Let us know if you have any questions!

Good Luck!

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Saturday, October 20th, 2007 AT 10:25 PM

FISHERMAN

MECHANIC
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OK.
When was the last tune-up on your vehicle?

A bad dist. Cap causes that problem. Plug EGR causes that problem. Bad wire causes that problem. Cloged gas filter causes that problem.

A good tune-up saves gas and extends your engine life.

Sooner or later you have to do it anyway.
Its your option.

Good Luck![/Quote:e5a5e30cab]

had the O2 sensor changed a few weeks ago. Since then, have been having the problem. Related? Could the heating element in the O2 sensor be bad?[/Quote:e5a5e30cab]

Could be.
But the ECM should detect any problem with it and light the "check engine"

try unpluging the O2 and "see" if the ECM detect it.

Its that an aftermarket O2 sensor?

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Saturday, October 20th, 2007 AT 10:37 PM

BORGS8

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9 POSTS

OK.
When was the last tune-up on your vehicle?

A bad dist. Cap causes that problem. Plug EGR causes that problem. Bad wire causes that problem. Cloged gas filter causes that problem.

A good tune-up saves gas and extends your engine life.

Sooner or later you have to do it anyway.
Its your option.

Good Luck![/Quote:feb108d973]

had the O2 sensor changed a few weeks ago. Since then, have been having the problem. Related? Could the heating element in the O2 sensor be bad?[/Quote:feb108d973]

Could be.
But the ECM should detect any problem with it and light the "check engine"

try unpluging the O2 and "see" if the ECM detect it.

Its that an aftermarket O2 sensor?[/Quote:feb108d973]

Had them put in a Denso, not a Bosch. Doesn't the tech "clear" the computer after the repair? Could be why I am not getting a light, or should a new light come on?

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Saturday, October 20th, 2007 AT 10:43 PM

FISHERMAN

MECHANIC
938 POSTS

Should be back as a "new malfunction".

But. I have the "feeling" that the problem its related to something else.
First, check the distributor cap and rotor for cracks and clean spark transfer bars (inside of the cap)
and the MAF sensor (clean it)

after that we continue with the troubleshooting.

It could be something as simple as that!

And the O2.A coincidence!

Let us know!

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Saturday, October 20th, 2007 AT 11:06 PM

FISHERMAN

MECHANIC
938 POSTS

Here`s how to clean the MAF sensor:

use a brake cleaner. "does not leave a film or residue". do not use a qtip because you don't want to physically touch the MAF and risk getting any pieces and strands of qtip getting stuck to the temp. sensor and the 2 hidden wires that are inside the MAF Sensor.

Do it with care!

Hey!!! I saw that you Donate!! Thanks a Lot!!!

We appreciate your support!

Here how it looks before:

After clean it: Look closely the sensor (the little bulb)

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Sunday, October 21st, 2007 AT 12:05 AM

BORGS8

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9 POSTS

Thanks F-man. I am on it. Hope the modest donation goes directly to you for all your help! Found it. The MAF looks very clean. The bulb is still brown and I can see the filament inside the glass. I shot some electronic contact cleaner in there though to avoid residue of brake cleaner. Sort of expected this though because I am religious about replacing air filter regularly with a Denso (no oil) filter. Now what? I am going to run to Auto Zone and get a diagnostic, even though CEL isn't on.

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Sunday, October 21st, 2007 AT 9:16 AM

FISHERMAN

MECHANIC
938 POSTS

Hello !!

Did you got any "codes" on the scan ?

did you check the dist. cap?

What kind of spark plugs are you using?
did you replace them 30 k ago?

How about an EGR ?

An EGR clog Can cause a rough aceleration ..
But if stuck open a bad idling too....
And you have a good Idling...
check it anyway that way (process of elimination)..

BTW:
the donation Help us really good, we are a team of volunteer mechanics and a good staff of engineers that support the site, we`re people helping people...
the donation keep us on line!

thanks a lot!

let me know on your findings!

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Sunday, October 21st, 2007 AT 8:49 PM