got the P0442 code yesterday, once cleared or reset how long till the system goes through its paces and would trigger it again if the problem didn't get fixed?

 

There is no amount of time you can put til it pops up again... Unless you just cleared the code and didn't fix the problem that caused the code..it could show up the next time you drive it.

Heres a few things that will cause that code to pop up.

1. Defective or loose gas cap
2. EVAP canister or hose cracked- not connected
3. Purge or vent solenoid defective
4. Vaccum leak at engine

Have you checked/fixed any of these things?