I am changing my own spark plugs for the first time. I have a spark plug wrench, dielectric grease, anti-seize compound etc.
I have a Haynes manual for my 2002 Toyota Corolla. The book was written before Irridium plugs were used. Should I tighten the spark plugs to the same torque specifications as regular plugs? The book says 158 inch pounds. How do I know I have tightend them to the right amount?
How do I avoid cross threading the spark plugs? What happens if you cross thread the spark plugs (assuming the car seems to be running fine)? Would I need a new engine or expensive repair when it is time to replace the spark plugs again?