2009 Tribeca 3.6\nMy son thinking he would help his dear old dad pulled #1 plug and determined the car needed new plugs. Auto zone got plugs AZ says will fit,\nInstalled plugs... result... misfire cylinders 1, 4 &6\nSo at 162,000+ miles I got all 6 new coils..result...4&6 still misfire\nNext replaced all 6 fuel injectors..result...4 still misfire\nswapped plug,coil and injector with working cylinder #5..result...4 still misfire\nchanged plug end to coil on #4..result...misfire\nAny ideas on what a plug change could do to cause misfire or ????.. My son feels like crap, but he meant well. At 72 I still operate by if it ain't broke don't _____ with it!\nCheck engine light flashes. My neighbor used his OBDII/EOBD+CAN to read failures as parts were replaced.