Bleeding/Missing Tech help

[Fisher, Scott]

Mark Woodland writes:

>2. The '87 5KTQ has an intermittant low-load miss, from 1500/1800 up to
3000
>rpms, at which point it smooths out and pulls like a train up to redline.
>I've tried new tri-electrode plugs, wires, cap and rotor, as well as
>multiple applications of Techron injector cleaner, all to no avail.

I just had almost exactly the same symptoms in one of my non-Audis (1974
Alfa
Romeo Spider Veloce, to be specific).  I'd get bad stumbling and bucking at
3500 RPM plus or minus a couple hundred, but from 4000-7000 it was smooth
and
lovely.  Reasoning suggested that the only thing that would cause erratic
running at the midrange would be failed distributor advance: below the point
where the advance comes in it runs fine, and after the point at which
advance
finishes it runs fine, but in the middle it's erratic.

To check for this, I pulled the cap and twisted the distributor rotor by
hand
to see how it felt.  It felt floppy and loose when compared to a known good
distributor in a friend's car.  The local Alfa shop agreed with my diagnosis
that the original 28-year-old weights had simply worn out.  I acquired a
newly
rebuilt distributor, installed it last week, and have solved the problem.

Since you mention low load as a condition for your miss, I would look into
any
vacuum advance mechanisms your '87 5KT has (I don't know the 5KT at all).
But
because vacuum is used on other cars to modulate advance under load, there
may be some interaction there -- possibly a leak in the advance tube, or a
tear in the advance diaphragm (again, if your distributor has one -- turbos
not being known for producing much in the way of vacuum :-).

Best,

--Scott Fisher
  Tualatin, Oregon
  '61 365B T5/'74 Spider Veloce/'83 Coupe GT/'93 100CSQ