I have a 2004 mustang with those issues. My mechanic ( not ford), says it is
the vibration damper on the engine.
Car is now in service at the Ford dealership.  Plenty of warranty remaining,
so I'm not too worried.  Let's just wait and see the BS they shoot back at
me (I've had bad experiences there before).  Anyway, it's likely that their
claim will be that they couldn't find anything wrong during a road
test....hmmm, yeah.....heard that one before.  Anyway, I will try a code
reader if they can't solve the problem.

Thanks,
Just A Guy
"Just A Guy©" <andrewhunt@nf.sympatico.ca> wrote in message
news:9ShAe.59429$Ph4.1752025@ursa-nb00s0.nbnet.nb.ca...
Hey,

Just got back from a weekend excursion, and while cruising along the highway
I noticed a 'rough' vibration in the handling of my '04 V6 between 2500 and
3000 rpms, noticeable only in 3rd and 4th gears, but much more profoundly in
4th gear.  Acceleration also seems to be restricted in this rpm range and
shifting down to 4th from 5th to pass the Sunday drivers has become more of
a challenge than a slight adrenaline rush.  I assumed a wheel alignment
issue may have been the culprit, but then I asked myself why I would be
experiencing this loud roar and vibration in the engine bay at consistent
RPMs, not speeds.  Could a wheel misalignment still explain this activity?
Or should I be concerned of a more serious problem.  Also, I believe I could
smell faint engine fumes when pushing the engine (i.e. when trying to
maintain speed during uphill climbs), although this may have been the
exhaust fumes of the hundreds of other cars on the highway.

Also, at very low speeds (1st and 2nd gears), I can hear a faint, fast,
repetitive clicking in the engine bay, audible only to the trained ear,
something I had not heard until today.  In addition, I hear a distinct
'click' in what I believe is the front axle when I turn the wheel to the
left only (while both moving and idling).  Brake caliper issue?

I'm not sure if these problems are related or independent of one another,
some of which may be my overactive imagination!  Nevertheless, there is
nothing worse than an unreliable 10-month old Mustang.  Having already lost
a 2000 mustang last summer, my conscious exaggerates every sound, smell,
vibration, and sight that appears to be out of order with my '04.  However,
being slightly obsessive-convulsive with regards to cars can be of
benefit......kind of like an early diagnosis of a treatable cancer in a way!

Anyway, if you have any suggestions, solutions, explanations, please let me
know.

Thanks,

Just A Guy