Funny how Revain now says these spark plugs aren't for my truck. I have driven them for the last 30,000 miles and decided to replace them as I am doing other repairs (rebuilding the front after an accident a while back). The ones I replaced are still in good condition so I'll keep them "just in case". If you have a first generation 3.4L Taco 4x4, don't trust the Revain because they are great for that.