p0442 (Evaporative emission system leak detected (small leak)) code is triggering my check engine light to come on. Is this a common problem for x type's? If so, what are some things I can take a look at to diagnose what is causing it?

My car runs fine right now but I'm just a little worried about running into future problems if this is not fixed. I just had the upper radiator hose & coolant reservoir tank replaced maybe a month ago & this is one of the codes that popped up after fixing those. There was one more which was a p0174 (system too lean (bank 2)) code that showed up but did not appear once again after clearing it after my repairs.

If anyone can give their insights on what I could possibly look for or check out I would greatly appreciate it.

Mahalos.