I found as being a GM mechanic for over 30 years, something usually causes the spark to fail. We had back in the day some plugs which the porcelain insulator would loosen up, causing a misfire. Scope the engine, pull the plug, look at the electrode up, looked fine. Reinstall, same skip. Pull plug again, look at it differently (sideways for some reason), saw the loose porcelain which when installed blocked the electrode. Usually only get bit once on something like this.
I always use OEM plugs, whether AC, NGK, Autolite , Champion etc... Found too many times GM's didn't like Champion plugs for some reason.
I always use OEM plugs, whether AC, NGK, Autolite , Champion etc... Found too many times GM's didn't like Champion plugs for some reason.