Chips don't work on a 12 valve, they're all mechanical.
That's why the PCM flash can't have changed the way the engine runs.
My bet the problem is with the tranny programing.
People with '96s often get the flash done in order to use a tranny lockup switch.
'96 is the only year that won't work without the flash.
Perhaps you should hook up an easy and cheap to do lockup switch.
Instructions> http://www.tstproducts.com/Torque Converter Lockup Switch.pdf
That's why the PCM flash can't have changed the way the engine runs.
My bet the problem is with the tranny programing.
People with '96s often get the flash done in order to use a tranny lockup switch.
'96 is the only year that won't work without the flash.
Perhaps you should hook up an easy and cheap to do lockup switch.
Instructions> http://www.tstproducts.com/Torque Converter Lockup Switch.pdf