First off, welcome.
Second, there is a plethora of information that can be had by using either the search function here or Google.
Third, welcome again. :banana:
Some info from the link in my sig.....
here...Powered by Google Docs
Causes for P0505 according to the FSM are
1. Air induction system
2. Electric throttle control system
3. PCV valve and hose
There are some diagnostic checks in the FSM you can do before swapping it. (somewhere around page SF-35--that's for '99--online may be different). There are some threads on trying to repair it, too.
Or you can just throw parts at it.....your choice. Oh yeah, welcome!