Clicking noise in engine?

[fooch]

There is this clicking/rattling noise in the engine when the car is in drive or reverse. when i give it gas though the noise goes away so i only hear is when I'm going 5 mph or slower. the rattling noise is kinda fast and can clearly be heard outside next to the car and in it with the windows down.
Anyone know what could be up?
Its an 02 xlt

 

[titansarrow]

lifters maybe? mine's doing the same thing, at all times though