When tapping lightly on the maf sensor with a screwdriver the idle
stumbles and cuts off. The reading on scanner for the maf
sensor goes from 2.02
to 16.36 in the two frames which I was tapping on
it and it cut off. I've tried
replacing it with a cheaper a1 remaned a1
cardone unit, which I should know
better anyway, having sold the p.o.s
products by that company for a few years,
but I never said I was smart.
So my question is, does this mean that my oem unit
is bad being that it
cut off and possibly the reman was a defect out of the box
which I know
could be possible? I checked the fuel pressure and it's fine,it
loose pressure after sitting for about an hour with the car off, so I
believe none of the injectors are stuck open. All the plugs are very
sooty. At first it had a code 0174 but I've noticed once u
mention that everyone
ignores u. I've looked thru post after post on
every 0174 issue and none compare
to my problem. And I haven't located a
vacuum leak yet. Any intelligent
suggestions would be appreciated.
Back in the mid 80s on Buicks with Delco MAF sensors, the test
was to honk the horn, if the engine stumbled or died, the MAF was
Scroll to the bottom of this page;
It's a volumetric efficiency calculator, you can use it to
determine whether your MAF is reporting close.
Do WOT while recording your MAF PID, plug in the numbers and see
where you're at. (no VE calculator is 100% exact, but this one is
Also, what is the BARO reading from your scan tool, does it jive
with your altitude? Since BARO is extrapolated from MAF on
Fords, if the MAF is skewed, so might the BARO PID.
If you can graph data PIDs, graphing fuel trims is quite useful,
if one bank goes negative and the other bank goes positive, I'd
be looking at a restricted exhaust.
I got it running semi normal (for it anyway). MAF sensor was bad and the
hose that runs from the back left to the back right of the intake
then to the
pcv in the right valve cover was leaking in two spots, one
at the rubber Tee on
the back right and the rubber hose that connects
the plastic hose to the back
left intake had collapsed and split. The lt
ftrm2 is still a bit off from
normal. Could it possibly need a new o2
sensor? All the rich running playing
around I did diagnosing it might
have fouled it? Thanks for the help so far.
Rotten PCV hoses is so common on 4.6s, I'm surprised it wasn't
suggested very early on.
Before you throw any O2 sensors at it, the new MAF needs to
figure out what altitude you're at (it doesn't measure altitude
directly), make some occasional wide open throttle runs over the
weekend and then check your fuel trims and BARO PID against spec.
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