Hey guys, My 03 Suburban has 153K on it, unknown whether the plugs have ever been out of it. I did a search of the forum for spark plug topics, none really answered my question. The aforementioned topics referred to service bulletins and specific AC Delco plug numbers for the pre and post '03 - '04 model year. Given a choice, do you stick with ACD, switch to NGK, or go with some other brand? I, personally, like to stick to OEM or name brands that are trusted by the industry, but have been out of the game long enough that I no longer know what brands are acceptable and those that should be shunned like the red headed stepchild of [censored]!