There is a knocking sound especially when acclerating above 40 mph. It sounds like valve chatter but I'm convinced that is not it. You can hear it above the radio. The sound seems to be coming from in behind the console near the passengers side. I have taken it to the dealership 4 times and it never makes the noise when I take it and they have no idea what it might be. Just curious if anyone else has had a similiar problem. Thanks.

I don't have a 'knock,' but if I drive her for over 5 minutes and turn her off, i get a pinging or tapping sound from the engine. My old Grand Prix did this, but I have yet to hear any other engine do it. We might be talking about the same thing though. My dealer told me it was normal?? But then again they blame my window problem on my in channel vent visors, so...

I just got my 2004 SE back for the same problem. They had to replace the exhaust manifold which was labor intensive. This is a problem and will be in a service bulletin soon. My part was on back order for 2 weeks. The problem is solved

I finally got that loud chatter out of the engine. There is a service bulletin on this problem, FINALLY! They installed a ground cable from the battery to the right cylinder head and eliminated what they called a "spark knock". I like the Armada so much better now. The noise would drive you crazy especially coming from a brand new SUV.