Spark plug Bosch or AC DELCO

Use only AC DELCO ignition components for GM vehicles, and that includes spark plugs. The factory plugs work perfectly.

AC Delco CR43TS.

Copper plugs are actually the best for performance, precious metals just last far longer.

if you want to save a bit and still want some quality get bosch plugs those are good too, I’ve used them before and they were pretty good as well.

I'd use the original equipment AC Delco plug. Rockauto has them for $6.31 each, with a $3 per plug rebate offered.

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

Bosch spark plugs aren't bad, per se, but they're not really anything special.

I recently just replaced my spark plugs they were past due. So I bought the OE Bosch 9683. The engine runs fine, starts easy, no misfiring, no rough running. But after the plug change I am getting much worse millage.

Those spark plugs are junk, and on top of that, they are now carbon fouled. I would strongly encourage you to install new, normal, spark plugs.

I ended up checking the ignition timing again, put in a new coil, new knock sensors, put in another fresh set of plugs, set the DPR MA to +5, and I failed my emissions test with the same results.

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.