I have a check engine light and the codes that are pulled are 171 and 174
bank one and bank two too lean, I have changed the O2 sensors, the mass
air, flow sensor throttle position sensor and the light comes back on,
short of buying a break out box for 500.00 I could use anyones advice

"einbit" <einbit (AT) yahoo (DOT) com> wrote

start with a fuel filter, they are lots cheaper than all those sensors and
should be replaced every 25K or so anyway. A plugged one will give you a
lean code. If that doesnt fix it, it's time to get a fuel pressure
gauge.(also cheaper than all those sensors)

I should have added that its a V8, I will change the filter tonight what
pressure should fuel system be at? Is this with key on engine running or
just key on?

Lean can also be caused by a vacuum leak. I just fixed the same codes on my
'95 V8 by replacing a short rubber hose. The PCV valve has a short rubber
hose at the valve, a metal line, then another rubber one to the throttle
body. Mine had a bend at the TB end and a huge hole by the time I found it.
I couldn't see it but I heard the vacuum hiss with the engine running.

PoD

"einbit" <einbit (AT) yahoo (DOT) com> wrote

Fuel pressure should be checked when fuel demand is high.... a brief wide
open throttle on the highway should tell any tales. While a pump can easily
create pressures in spec when fuel demands are low, this same pump may be
tired and unable to supply sufficient volume at high demand conditions....
this insufficient volume will show as a drop in pressure.


"einbit" <einbit (AT) yahoo (DOT) com> wrote

"" wrote:
well you wasted your money on buying o2 senors and maf sensor, MAF
sensors can be cleaned I never herd of a TP sensor creating this code
you have a vacuum leak either intake manifold gaskets or vacuum lines
check them very carefully If you have a scan tool curious what is your
Long fuel trims and your short fuel trims long should be 0% +- no more
than 10% short should be hovering around 0% this is why it pays to
bring your vehicle to a dealer, I would have fixed your problem for
less than you spent on wasted parts

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"" wrote:
If your fuel filter is restricted you will notice a lack of power at
wide open throttle ck the vacuum lines for leaks see it all the time

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"" wrote:
32 to 38 PSI press will not tell you if you have good fuel flow you
can have normal press with poor fuel flow

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"Marty" <UseLinkToEmail (AT) AutoForumz (DOT) com> wrote

Its nice if you can hook up the gauge and run the hose from under the hood
and drive the car. That way you can see the pressure under real conditions.
Just take a fire extinguisher with you

I do know that the only time the light comes back on is when she is getting
on the interstate, around town it stays of only when