2002 Dodge Caravan that's misfiring

Seems that mechanic likes job security to me.!!!! when you do a tune up and comes back misfering all us mechanics know that is a defected spark plug or in most cases the spark cable came loose or rubbed on something hot or it came loose. if you have the van at home turn it on at night comptly somewhere dark and stare at the engine and youll see static runnning loose like thunders at night and you ll see the problem. then use a flash light and check what happening. or youll will also hear like a whipping sound, i helped people in the past so many times this way remotely and it has helped them.