Originally Posted by VALKRYDERGUY
I admit I never read the manual front to back but as far as it saying spark plugs 100,000 miles or 5 years sounds odd to me.
Miles I agree but how does the age of a spark plug affect it's performance ??
I believe the primary reason to change plugs after 5 years is to protect the aluminum heads.
Plated steel plugs sitting in an aluminum head may well become impossible to remove without damage if left in too long.