knocking

My 05 Altima 2.5 (manual if that helps) has been experiencing a troubling knocking noise. I was hoping all you fellow Altima enthusiasts and mechanical experts can help me out please. I can't identify where in the engine is rattling exactly but it gets louder when I accelerate and still rattles...

I have a 2000 Altima GXE and just discovered I need to change the front control arm bushings. Is there anywhere with step by step directions on how to do this on my own or is this a job I would need to take to the shop? Thanks

I have a 2007 Altima 3.5 SE 6-speed manual. Recently I have noticed that there is a hissing noise (almost like a short air burst noise) occurring when I go over a speed bump or any sort of bump on the road and my dealer told me that was normal; is this true? Has anyone else experienced this...