Did they have to remove the upper dash to get to the centre speaker?
Our rattle has the same criteria as yours... car only done 20,000K's been rattling for the last 6,000k's... dealer has tried several times to track it, but no luck.
I have checked for the fuel line rattle, don't have it. Inserted foam packers and small sprays of canned foam also - preventative.
Have insulated and isolated both A-Pillars.
Have deadened both front doors with a full tear-down and reassemble with sound deadening kit and sealant.
Same with sunglasses holder and rear vision assemblies.
Deadened Scuttle panels and window wash spray lines/pipes under scuttle panels.
Had the Sound generator replaced under warranty as it had it's own separate internal rattle (a loose screw inside).
Foam strip isolated/dampened the new sound generator.
Rattle exists with Sound Gen off, but worse when on. Sometimes slightly worse in colder weather, sometimes worse on a warmer day... it's a real F'er. Def sounds like centre dash area near, centre speaker, Firewall, windscreen zone.
Got a '91 Toyota Levin GTZ that has less prominent rattles...
rattle.m4a
