normal plugs gapped to .8mm, iridiums a waste of money. just change plugs with every service. also just check your injector plugs(give them a push to make sure they are seated). also, take off your coil pack cover and in a dark garage or at night, turn the car on and have a look if you can see and sparks jumping around your coils. be aware that there will be light flashes caused by plasma, that will be normal. look for sparks