Rattle at high RPM/full throttle?

[ian@bluemoon.hplx.net (ian Butler)]

Hihi, everyone.

My 16v has had a curious problem for the past six months or so.  At high
engine speeds (5000rpm and over) and at full throttle, there's a nasty
rattle from the engine compartment.  I don't know if it's knocking, as I've
never heard knock at such high speeds before (my other cars have been
considerably more sedate than the Scirocco.)

It used to happen at partial throttle around 3500rpm and then went away
above that (until 5K).  A new exhaust, plugs, rotor, cap, and ICM later, the
3500rpm ghost disappeared, and I can also take it well into 5000rpm at
partial throttle without trouble.  The rattling starts at that speed pretty
much as soon as the second throttle butterfly opens.

I've guilted myself into not looking at it for a long time, knowing that I
probably shouldn't be racing around at such RPMs on public throughfares
anyway.  But I also can't stand it not running right and having that
capability.  Any ideas?

ian Butler / ian@hplx.net
'88 Scirocco 16v "Don't buy food, repaaaair me..", '87 Syncro GL