I would be suspicious of any NGK that don't plug the plug stock number stamp on the hex. Also you dissect the plug you will also the plug number on the insulator hidden under the metal crimp at the top of the hex. Or at least that is what I found last week while I was investigating CMR6H failures. For some they are shorting out at insulator just before the plug tip. Driving me batty so going try some Bosch plugs as replacements.
Last edited by AVB; 24/08/18 11:47 AM.
