2001 Mazda MPV Misfire

My MPV with 102,000 miles misfires when cold to the point that the check engine light flashes (code P0302). Within a minute or two it seems to run fine.

Local mechanic replaced plugs and wires ($460) and it was no better. Mazda replaced the intake gaskets and cleaned the injectors ($440) still no fix. The coil was replaced 8,000 miles ago. Help!