grenade throw not working in halo 3 on Xbox live. wtf?

[Will Anderson]

I press the throw button, my guy throws, the grenade flicks one second later. My mom thinks it's the wireless connection failing a bit.

 

[Dennis W]

Your mom is right as usual. Wireless connections aren't very good for XBL. What you are experiencing is the negative side effect of Host Advantage coupled with your own lag. When you throw a grenade on your screen it connects with the ground as usual. On everyone else's screen it appeared as though you threw it behind the person you were chasing, or in extreme cases behind yourself. You don't see the explosion either because it is off-screen and you just don't know it; or because your connection picked up enough to skip the frame the explosion was in.