5kCSTQ very sluggish

[TEX TERRY, II]

From: Dennis Unsworth <unzie at ixi.net>
(snip)
"Speedy" is now extremely sluggish under load after cold start-up. It's
been
5 months and we can't figure it out.
(snip)
Sputters and even backfires.
(snip)
Fuel system's been checked -- distributor, pump, warm up regulator. Filter
is new and lines ok. Vacuum hoses ok, temp sensor's been changed, ignition
and timing ok.
(snip)
Would an old timing belt cause this trouble?
(snip)
'86 5kCSTQ; 220k hard miles
(snip)

How did you verify the timing as being "ok"?  The symptoms you have
described above sound like the timing is off spec.  If the timing is being
changed underload, then either the belt is jumping teeth, the distributor
housing is turning, or the distributor advance is not moving freely.  Have
you looked at the distributor to see if there are any cracks in the
housing?  Have you checked to see that the distributor mounting locking
bolt is indeed tight enough to hold the distributor case from moving?  Is
the advance mechanism in the distributor actually "freely" moving?  Is the
Hall sensor mechanism firing inconsistently due to old wiring?

Tex Terry, II
83 5kt sedan (non-quattro)
Franklin, PA  USA