Sorry it's not about an Armada but I just went through something I'd never ran into so I thought I'd share the story just in case anyone else runs into it on their truck...
I started to go to the store the other night in the Mini Cooper didn't even go a block when I heard loud tapping from the engine. I turned around and put it back in the driveway and popped the hood. Sure enough it was very loud coming from the valve cover. I looked and looked and didn't see anything strange, it was dark out. So I'm dreading the worst, a broken Piston Rod or Lifter, really hoping for the Lifter.... So next day I call the guy who worked on the Porsche I had, he said bring it by and I'll look at it for you and give you a professional opinion. So I picked up a U-Haul Car Carrier and pushed it up onto it last night then I stayed to work from home today so I could drop it off.
So I got there, we popped the hood, started it up and it was quiet. WTF??? Okay, so I rev it up a bit for alittle while to let it warm and sure enough there it was. So we're looking and looking then I happen to notice one of the Spark Plugs was moving... Hmmmm... that could be really good or bad... So we shut it off, took the plug out, the threads all looked good and there was signs of exhaust leaking out up and around it. So we put it back in and tightened it down, then checked to others, and the dadgumned thing is fixed running perfect again.
I've never had a loose spark plug before, he said that if it had been left then it could've very easily blown the whole piston out over the next few weeks.
2005 Armada LE 4x4