Exhaust manifold cover

Car: 2002 3.2 rodeo LS
SO i have a funy shimmy sound coming from the engine between 2800-3100 rpm and from looking around the forum it is one of 2 things

1. pinging - i have the correct spark plugs in and am running 89 otctane fuel with a fuel filter that is about 5k miles old a wix brand, oil is castrol part synth 5w-30 doesnt burn oil

2. exhaust manifold cover is loose / broken.

I am thinking #2. anyone have taken theirs out fixed it and put it back? Where can i get to it on the car?