Thanks for all the responses - the car is stock 155,000km. I have replace 5 of 6 coils with aftermarket, can't remember exact brand but they were cheap approx. $20 each. I used the ngk plugs with 1.1mm gap as car is still stock. Shaun - I live south of the river but happy to travel to have someone with expertise check it over. What is the best method to use to eliminate the coils? I replaced them originally because they looked sh*tty and had hairline cracks in the plastic and it did seem to solve the problem.