title_body: Keurig Coffee Maker gets clogged and slow
upvoted_answer: Due to the age and usage of your Keurig machine, I would say that you are experiencing two possible problems - one at a time or perhaps both.
  
  The Problems:
  
  
  The motor in the pump in your Keurig machine may simply just be getting worn out. If this is the problem, you should be able to hear it struggling to pump water out through the K-Cup. If you need a comparison, try comparing it to a newer model and see how it sounds. If de-scaling (see next problem) does not work, then you may need to replace the motor/pump. It may just be easier at that point to buy a new Keurig machine.
  The machine seriously needs to be de-scaled. I would recommend running a solution of 25% lemon juice and 75% water through the machine. Make sure to run around 250 - 500 mL (about one to two cups) of this solution from the tank all the way through to a cup. Then rinse with atleast 1 L of of normal water (about 4 cups).
  
  
  
  
  CAUTION:
  
  As I have stated in other answers, breathing the fumes from this can be extremely dangerous for your mucosa (parts of the eyes, nose, mouth, throat, respiratory tract, and lungs). Do not breathe in the steam or fumes. 
  
  This is not a huge concern with lemon juice (which is why I recommend it), but if you were to use vinegar or a commercial de-scaler, this would be a huge concern. 
  
  Just be smart about it. You don't want to end up with permanent damage to your respiratory tract.
  
  
  
  Other possible problems (harder to fix):
  
  It could be possible that a seal somewhere in the pump has worn out and air is entering the system as it is being pumped. This would involve replacing a seal and taking the machine apart though.
  
  There may be some other component, that I can't think of, that is damaged. Try the above solutions and leave a comment. Let me know if anything works.