At what interval should spark plugs be replaced.
depends on what sparkies are currently installed...100,000 miles are what we can expect from plantinum plugs~ back when I was a kid, before platinum was 20,000, but times are a changin' making everything I knew not valid in today's world~
You could change them "early" and they would last for another twelve years at the your 8K miles per year rate. You might see a small increase in MPG's.
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