Originally Posted by Jeepermat
Seriously, my Moms GM 6.0 has over 200k on it with the original plugs, Ive got a set in my garage for it, however there is no need to replace them as they look and gap to new specs.
Regardless of application if you are removing the plugs for ANY reason, you may as well replace them. They are cheap insurance. Just the act of removing them may damage them.
And you have already performed the labor of removing them, so replace them.
Not to mention the factory spec's intervals. Even your 6.0 should have a factory spec'd spark plug change at 80-100k
Most DOHC V6's spark plugs are typically 60k or so.
And before you say "they are still fine at 200+K miles" again...
They are not.
The rig may run "fine" but it isnt running as designed.