Idle is rough.

[kneel]

I just recently noticed the car is idling a little rough. What causes this.
Also what spark plugs should i have in the car with the KO4 upgrade? Could that be it. I went ko4 but never changed the plugs

[s42k5b]

could be a number of things. I just purchased bosch side-fire plugs, little pricey but i have heard nothing but good things about them.

[kneel]

could be a number of things. I just purchased bosch side-fire plugs, little pricey but i have heard nothing but good things about them.

where did you get them from.