Hi all. I just had a wake up call. I changed the spark plugs (On Santa Fe in sig) from OEM to Champion 9006 iridium. I did this at 90K. Everything seemed ok for about 12K miles. Gas mileage seemed unaffected. I now have 102K and my wife noticed a vibration when accelerating from a stop. I looked at everything I could think of. Motor and transmission mounts, CV joints, suspension, etc. I got to thinking about the plugs, so I bought a set of Denso Oem plugs. I gapped them to factory spec (they were close out of the box.). Started the engine and went for a drive. Smooth as can be. Have you guys ever seen this happen? I triple checked the champion plugs and the 9006 are the proper application for our car. The plugs I took out looked ok but the porcelain had some heat / discoloration marks at bottom. I am used to seeing that at 75k or more so I was surprised to see it at only 12k. Lesson learned. Go OEM.
