My 2014 Mazda3 developed an irritating rattle after 3000miles when going over manholes or badly filled potholes. Speedhumps didnt cause the noise - only when the front offside encountered a slight dip in the road. I thought the sound was from the Door Sill or at the seat adjuster and may have been plastic hitting metal. I found similar stories on the US Mazda3revolution.com forum so booked car in -mentioning the TSB for good measure .

The dealer also found the Mazda TSB (Subject Rattle noise from Bottom of A Pillar Bulletin 09-001/14) which states a clearance is needed between the wiper bracket and the cowl.dash panel. The service manager was surprised that a gap of 0.5-1mm was all that was required. My 3 was probably one of the first on UK roads (1st week Jan 2014) so 14plate ones may be ok.

Hopefully anyone with this fault wont end up with a dealer pulling the trim apart trying to find a rattle or being otherwise fobbed off.