You are correct on the 31 code. Check for a blown fuse and cracked or split vac line in the evap system.

 

You could have gotten the same code list from this website by looking at one of the STICKIES that are always on the top of the forum - FYI.

As for error code 25, it may be a holdover from when idling WAS a problem. You can disconnect the battery for 30 seconds to clear all the old error codes thrown. Ignore codes 12 and 55 if you see them after re-connecting the battery as you SHOULD see these two codes.

If error 25, comes back, they you may still have an issue with the IAC - that either a cleanup will help, or a replacement will fix. I hope that you have taken off and cleaned the TB, IAC, and TPS already, but if you have not, please do so.

As for error code 31, if that error returns, then you need to check the vacuum lines as stated earlier AND you really need to try and clean it. They really get gummed up under NORMAL circumstances, and after 7 years of neglect, I cannot imagine how it could NOT be gummed up!