01 JEEP MISFIRE

my 01 jeep grand cherokee laredo is misfiring.  My mechanic replaced the ignition coil and said it was fixed.  Next day, happened again.  Brought it back, he replaced something else, said it was fixed, next day, happened again.  Brought it to another mechanic, and it’s been there a  month and he cant figure out what’s wrong with it.  Any suggestions, or anyone had similiar problems and was and how was it fixed?  HEEEELP