Newbie question regarding fuel pump noise/other tech advice

[RM]

Probably sounds like a fuel pump.... I'm not sure of the set-up on a CGTq
(if they have one pump or two) but it sounds like the main pump is failing.
IF the sound comes and goes or seems to 'warble', then it may be a fuel
inlet problem, or a clogged tank screen. One thing to keep in mind, and this
goes for all audis... If you neglect to change your fuel filter regularly
and it begins to clog, the obvious result is that the fuel pump needs to
work harder to pump fuel to the engine. This in turn puts a strain on the
rotor/pump mechanism, pre-loading it back against the bearings and housing.
It will tollerate this for some time, but slowly it will wear away at the
bearings. Once a new filter is installed and excessive pump load is
allieviated, the rotor/pump return to the normal location only to find that
due to bearings that have been stressed and are no longer tight, the unit
will now have lots of slop (as it's no longer preloaded due to a pushing
against a clogged filter). In very short order, the pump will lock-up as the
loose tolerances will cause either the bearing and/or the pump hubs (going
into the bearings) to fail. Moral of the story is to change your filters
frequently.

Rolf Mair