I have a 2002 Impreza RS 2.5 with 105,000 miles on it. No engines issues to date, except for last night... 
  
All of a sudden on a back-road an engine knock started along with a loud grating / high pitched sound. If I accelerate substantially, the engine gets rather rough, indeed. Oil level is fine, as is transmission fluid levels. 
  
I dug further and found what looks like a wire junction with two leads, one of which seems severed. 
  
Here is a photo: 
http://www.flickr.com/photos/blakespot/12057583596/ 
  
And here's the max zoom on that photo: 
http://www.flickr.com/photos/blakespot/12057583596/sizes/o/ 
  
Can anyone tell me what exactly those cables and that white, plastic junction box are? Does that look right to you? Thanks much. 
  
  
  
  
  
bp