I recently had a pioneer Avic N-3 installed in a 2007 Lincoln Executive L everything works fine except navigation cant hold 2-3 bars on satellite reception indicator so it goes off location starts giving wrong turn etc.Since the Xm plays fine replaced the GEX-P10XMT figuring it may have been bad,but by this time was frustrated and installed a Garmin Street Pilot for a back up I loved my last Garmin but I'm getting the same response lost satellite reception,so my question?is there a special ground or blocker that is specific to the Lincoln towncar causing this problem.Anyone know where I might find answers and solution to this problem?Help