Occasionally (when it's warm and I'm in a traffic jam) my brake pedal will
slowly sink to the floor. It will still give good stopping power when
pressed quickly, but for a long application I have to re-depress the pedal.

Is this a vacuum problem?

Thanks for any advise,
--Art
(91 Integra -- hope it's all right to ask here as I don't get the Acura
newsgroups)