'Check engine' light is on. Auto technician ran computer diagnostic. He
said the code showed the 'engine is running lean'. The fuel filter and
PCV have been replaced, but we still get the computer code 'engine running
lean'. No visible vaccuum lines off. Technician then smoke tested the
engine. Two items showed visible smoke; The EGR valve showed very little
smoke. The Idle Air Valve showed more smoke than the EGR valve. The tech
suggested replacing the 02 sensor. Can the tech be right about the 02
sensor? Also, I am told there are FOUR 02 sensors on this car. (1997
Mustang GT) How can you check to determine which 02 sensor is bad?
Please give dtailed response. Rather than just buying parts, I'd like to
try to determine what part is actually bad. If you do not agree that the
02 sensor(s) are the problem, please explain why and suggest what I should
do.

In article <8837d6c7c6411199d123617bde28f29f (AT) localhost (DOT) talkaboutautos.com>, Bear1MustardSeed wrote:
Possible, but the O2 sensors usually throw their own codes. The offending
one might not be bad enough such that it does.

Yes, there are four.

I can't because Ford publishes that in a separate manual that was out of
print when I went to buy it. But generally speaking I believe it's a
difference in voltage output that you would need to look for.

What is the specific code number?

"Brent P" <tetraethylleadREMOVETHIS (AT) yahoo (DOT) com> wrote

Bear1MustardSeed wrote:
Perhaps, but I it is my understanding that the O2 sensors are a consumable
part and after 10 years probably should be replaced.
The Heated Oxygen Sensor (H02S) detects the presence of oxygen in the
exhaust and produces a variable voltage according to the amount of oxygen
detected. A high concentration of oxygen (lean air/fuel ratio) in the
exhaust produces a voltage signal less than 0.4 volts. A low concentration
of oxygen (rich air/fuel ratio) produces a voltage signal greater than 0.6
volts. The H02S provides feedback to the Powertrain Control Module (PCM)
indicating air/fuel ratio in order to achieve a stoichiometric air/fuel
ratio of 14.7:1 during closed loop engine operation. The H02S generates a
voltage between 0 and 1.1 volts.

The technician did not tell me what the code was but he said that the code
indicates that the engine is running lean. Please advise.

Isn't the " Check Engine light" ONLY for emmisions crap..


"Bear1MustardSeed" <bear_detective (AT) nospam (DOT) yahoo.com> wrote

In article <g8J_h.158310$DE1.141776@pd7urf2no>, Idao wrote:
yes and no. Yes it's about detecting emissions issues. however emissions
problems often mean something isn't right that you should attend to
regardless. For instance, a misfire code, just because it's so small to
only be detected by the computer doesn't mean you don't want to fix it

On Fri, 04 May 2007 12:00:50 -0400, "Bear1MustardSeed"
<bear_detective (AT) nospam (DOT) yahoo.com> wrote:

:>The technician did not tell me what the code was but he said that the code
:>indicates that the engine is running lean. Please advise.

My advice is ask him for the specific code and get a print out of what
the code means. He should be able to give you that right off the
code machine. With that maybe people can be more helpful in narrowing
it down for you.

It could be that the fuel pressure regulator is bad and it may actually be
running lean.take it to auto zone,they will read the code and give it to
you.
"Brent P" <tetraethylleadREMOVETHIS (AT) yahoo (DOT) com> wrote