Code five misfire, rough running

Code number five cylinder misfire. Running rough, shutters under load, hesitates, tries to shut off from park to drive. Tested spark firing with light, all same except number six, fires erratic and irregular. Changed spark wires, plugs (NGK with P suffix) coil, and MAF sensor, PCV valve, cleaned IAT and throttle body, new high octane gas, new gas filter. No vacuum leaks, does not appear to have intake gasket or " o" ring problems. Shifts hard at times, sometimes slow to shift gears, and occasionally will drop self out of overdrive at high speeds. Could it be PCM? By the way, does not have EGR or DPFE on this year model.