I have to admit, I've never changed spark plugs since I've always had a diesel.
so, how do I inspect them for wear and gap them, etc. Plus where can I buy non resistor type locally.

The E320 just hit 90k so the 90k service is going down under my hands. It wont all get done today but it will all be addressed before the next tear off page in the service booklet.

Doing the oil today as well. I think I have a blackstone labs thing to send it out in for ha ha's