I replaced the plugs in my 2000 Silverado with these at 60,000 miles, although the orig. plugs were supposed to be good for 100K, and I wasn't experiencing any problems. Sort of a preventative maint. thing. Today, the "Check Engine" lite in the Silverado began flashing, and there was a slight roughness in the engine. After some troubleshooting with an OBD II tester, and finding #2 sparkplug to be the problem, after 41K miles. It appears these plugs are platinum with a 50K life span, compared to my original iridium plugs with a 100K life span. Iridiums will go in this time.
Ordered plugs 41-932 from Titan Direct . I inquired of Titan if they had 41-932 plugs, which were the plugs orginally installed in my car and they confirmed. The plugs sent were 41-993, which is an Iridium replacement for the 41-932. The replacement plugs fit and work perfectly...just not what I ordered.