my gps goes out(gets lost) when I drive a certain route and takes a while to on 2005 Lexus GX470

correct itself, now the gps light is out most of the time but if it is on then I can drive the route and no issues, the route is 264 to west to new hope rd in ral nc, this exit is not on my dvd I updated my map dvd in 2009 I have a 2005 GX470

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