Hi all,my car has developed a bad misfire this morning and sounds like a small subaru. I drive the car home 10 mile fine from work with no problems,started to reverse it into the drive and it started to chug. I checked the coil packs 1 at a time and when i removed number 3 it made no difference so i though great,sussed it,easy fix,went and got a coil pack but its still doing it

Would plugs be the next thing to change? The car is a 1999 agu 1.8t
Any help would be appreciated
