Hey guys...I'm having a problem with my 2004 FX4. It is shaking rather violently at idle, like it's about to die. Acompanying this issue, there is also a rapid "metallic tapping" noise, though I can not discern where it is coming from in the engine. I'm not all that experienced with engines, and this is the first time anything like this has ever happened to a vehicle of mine. Any ideas? I look forward to any help. Thanks

 

dont sound good...any DTC codes...CEL light

 

I don't have a code reader. The CEL came on just before all of this started, which was about 4 days ago.