Thanks Mr. Shiftright for the suggestions. We don't live in Marin County, but our Lexus NEVER had such problems in the same region of daily travels! One time I got the Acura rep at the SF AutoShow to admit that they used cheap components on the 1st run of the MDX models, but this is a 2005.
Needless to say, we are not impressed with such poor quality of the reception and the sound that comes out of the Bose system. Our 1st impression of Acura are not that positive compared to Lexus.
Having said that, I did manage to find a service bulletin on the AM Radio Reception. But does that mean, the dealer has to fix it for free!?
Thanks again for all your suggestions and help.