Spark plug Champion or AC DELCO

At least with double iridium ACDELCO on the c5. It’s 100k intervals.

AC Delco double platinum spark plugs belong in that engine.

Champion iridium. Champion makes the Mopar plugs. It's the closest thing to the original plugs without having to spend $30/plug.

I use them. Just replaced a set after they'd lasted 90,000 miles, only to rule out a very very tiny misfire count issue I've noticed lately. I might get a coil pack now, but those original plugs surely would have lasted longer (they say they should last for 100k).

I replaced them with AC Delco 14 Platinums, and it seems to be running better.

Just did mine with ac Delco, gapped them in advance and running great!

I have measured resistance above 5k and determined the plug to be causing a problem. Typical resistance is 1-3 kOhm, sometimes less for a new one.

These look like knockoff acdelco plugs.

Avoid Champions. Use NGK or Denso. Don't go cheap on plugs because the job is labour intensive.

Bought a set of iridium plugs that were wasted after 15k miles. Amazon gave zero fucks. AC Delco gave zero fucks. The scum bags who sold them changed their name and keep selling.