95 Mercury Cougar - EGR Bad?

Ok, let's try this again - I apologize for my original vague posting.
You guys have helped me out a lot in the past, hopefully you can again.

95 Cougar, 4.6 V8, 119,212.7 miles

My check engine light came on after the car had just been sitting for a
couple of weeks. I got Auto Zone to read the code, which turned out to
be:

P1407 EGR No Flow Detected

Does this actually mean the valve itself is bad, or just that a sensor
SAYS it is bad? How would I diagnose / repair this - it is making the
car run kinda rough. The AZ guy said it could be something as simple as
the gas cap being bad, but that P1407 code sounds a lot more specific
than that : )

I have located the EGR, it is conveniently located behind the intake
crammed into a tiny space against the firewall. I am really hoping I
don't have to remove it : )

Thanks,
Libby

In article
.com>,
"Libby Chantel" > wrote:

> Ok, let's try this again - I apologize for my original vague posting.
> You guys have helped me out a lot in the past, hopefully you can again.
>
> 95 Cougar, 4.6 V8, 119,212.7 miles
>
> My check engine light came on after the car had just been sitting for a
> couple of weeks. I got Auto Zone to read the code, which turned out to
> be:
>
> P1407 EGR No Flow Detected
>
> Does this actually mean the valve itself is bad,

Not necessarily.

> or just that a sensor
> SAYS it is bad?

Could be the sensor or the hoses that attach it to the exhaust
system. Could be plugged passages in the intake manifold.
Could be a problem with the EGR vacuum control.

> How would I diagnose / repair this - it is making the
> car run kinda rough.

All trouble codes have a published diagnostic procedure.

> The AZ guy said it could be something as simple as
> the gas cap being bad, but that P1407 code sounds a lot more specific
> than that : )

The AZ guy is an idiot, that's why he works at AZ.

> I have located the EGR, it is conveniently located behind the intake
> crammed into a tiny space against the firewall. I am really hoping I
> don't have to remove it : )

Most common problem on the early 4.6s is carbon plugging the
passages in the intake manifold.
Cleaning requires removal of the upper plenum (the elbow behind
the throttle body) and digging the carbon out of the passages in
the lower intake manifold.
The EGR valve itself is decidedly low tech and not all that
failure prone. The DPFE sensor and the hoses that attach to the
EGR pipe are high failure rate parts.

> How would I diagnose / repair this - it is making the
> car run kinda rough.

> All trouble codes have a published diagnostic procedure.

Ok, now we're getting somewhere. And the procedure to diagnose this
problem would be....

The first thing you should do is apply vacuum to the EGR valve while the
engine is running. If it starts idling rough or stalls then you know the
valve is working. If the engine continues to run smoothly chances are very
good that the passages in the intake are clogged with carbon.
Bob

"Libby Chantel" > wrote in message
ups.com...
>> How would I diagnose / repair this - it is making the
>> car run kinda rough.
>
>> All trouble codes have a published diagnostic procedure.
>
> Ok, now we're getting somewhere. And the procedure to diagnose this
> problem would be....
>

In article
. com>,
"Libby Chantel" > wrote:

> > How would I diagnose / repair this - it is making the
> > car run kinda rough.
>
> > All trouble codes have a published diagnostic procedure.
>
> Ok, now we're getting somewhere. And the procedure to diagnose this
> problem would be....

More than I'd care to type here.

In a nutshell;
1) Visual inspection of EGR vacuum lines, solenoid, DPFE sensor
and hoses.
2) Verify EGR passages by manually opening EGR and noting RPM
drop.
3) Tee vacuum gauge into EGR vacuum line, run self test and watch
for vacuum at appropriate stage in self test.
4) Observe DPFE voltage with scan tool while manually opening EGR
valve.