Hi all,
I have a strange little problem maybe someone can shed some light on.
When I fill up my 99 Toy Tacoma V6 and start to drive the check engine light
comes on. So I go to Advance and he says it is a lean problem, and blames
bad gas. So another fillup and the light again which can be reset by pulling
the efi fuse and relay under the hood. I take a trip and the light comes on
by itself without a fill up, any ideas what this might be? Also truck has a
130000 miles on it.
Thanks,
Scott..
Mike - 07 Mar 2008 23:29 GMT
> Hi all,
>
[quoted text clipped - 10 lines]
>
> Scott..
What's the code ? P???
Radlocker@hotmail.com - 07 Mar 2008 23:39 GMT
> Hi all,
>
[quoted text clipped - 10 lines]
>
> Scott..
Maybe a dirty or malfunctioning MAF sensor could cause that. That
might fool the ECU into thinking the throttle's almost closed. Just a
guess.
BTW, an easier way to reset your CE light is to turn the ignition off
and back on again 5 times while the truck is in motion and without
disengaging the clutch in the process. It's easily done at any speed
above 30 mph in the proper gear if you plan ahead so there's no other
traffic to hinder while you're foolin' with your ignition. This works
only if the problem which threw the code in the first place has been
corrected.
Jeff Strickland - 08 Mar 2008 00:04 GMT
On Mar 7, 6:07 pm, "Scott" <n...@haha.com> wrote:
> Hi all,
>
[quoted text clipped - 14 lines]
>
> Scott..
Maybe a dirty or malfunctioning MAF sensor could cause that. That
might fool the ECU into thinking the throttle's almost closed. Just a
guess.
BTW, an easier way to reset your CE light is to turn the ignition off
and back on again 5 times while the truck is in motion and without
disengaging the clutch in the process. It's easily done at any speed
above 30 mph in the proper gear if you plan ahead so there's no other
traffic to hinder while you're foolin' with your ignition. This works
only if the problem which threw the code in the first place has been
corrected.
<JS>
A far easier way to reset the light is to use the Scan Tool. The OP is
already going to Autozone to get his codes pulled (that sounds dirty when
Bill Clinton does it), he should simply use the scan tool to reset the
computer.
</JS>
Jeff Strickland - 08 Mar 2008 00:01 GMT
> Hi all,
>
[quoted text clipped - 10 lines]
>
> Scott..
If you go to AutoZone, why don't you use the Reset function of the Scan
Tool? This is a far better way of resetting the Check light.
Lean can be caused by a vac hose that has come loose, or otherwise is the
source of a leak.
Use the Reset function of the tool to be sure you have actually cleared out
the codes, and write the codes down first, then write them down again when
the light comes back on. Come here and tell us all of the codes that are on
BOTH lists.
Fuller Wrath - 08 Mar 2008 01:42 GMT
spray a shot of carb cleaner into the air intake across the MAF sensor and
see if it goes out
> Hi all,
>
[quoted text clipped - 10 lines]
>
> Scott..
johngdole@hotmail.com - 08 Mar 2008 06:41 GMT
Malfunctioning MAF (clean very carefully, it's an expensive filament)
or vacuum leaks are quite common. So is plugged fuel filter/injector,
or valve deposits, or a bad oxygen sensor. In other words, quite a few
things that basically resulted in too much air and not enough fuel as
seen by the oxygen sensor, assuming the sensor knows what it's talking
about.
Please post the P-xxxx code. The fuel trims are probably pegged +20%.
Some OBD-II scanners can tell you that, as well as oxygen sensor
waveform.
> Hi all,
>
[quoted text clipped - 10 lines]
>
> Scott..
Anyolmouse - 08 Mar 2008 17:22 GMT
| Hi all,
|
[quoted text clipped - 10 lines]
|
| Scott..
I have had the same problem with my '99 Taco. Turned out to be the
Oxygen sensor.

Signature
Anyolmouse
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Fuller Wrath - 09 Mar 2008 04:42 GMT
Doesn't a bad oxy sensor usually manifest itself with poor drivability?
(rough idle, crappy mileage, reduced performance, etc.)
Mike - 09 Mar 2008 04:47 GMT
> Doesn't a bad oxy sensor usually manifest itself with poor drivability?
> (rough idle, crappy mileage, reduced performance, etc.)
Normally, yes.
johngdole@hotmail.com - 09 Mar 2008 06:12 GMT
Or the sensor may be bad, not set any code, and be hurting the
converter, setting the P0420 code (converter efficiency below
threshold).
If it's the oxygen sensor, get the new Bosch planar type (not the old
thimble) if possible.
http://www.boschautoparts.com/Products/OxygenSensors/PlanarO2
> Doesn't a bad oxy sensor usually manifest itself with poor drivability?
> (rough idle, crappy mileage, reduced performance, etc.)
skipfromla - 09 Mar 2008 07:31 GMT
>| Hi all,
>|
[quoted text clipped - 15 lines]
>|
>| Scott..
Sounds like an O2 sensor. Next time it comes on, take a drive to Auto
Zone. They'll put their computer on it and tell you what the problem
is for free, or at least the one I went to did.