98 civic intermittent evap code

For a while my car will throw a p1456 evap code but sometimes it doesn’t and the system completes the test.

I’ll randomly hook up my obd2 scanner and it’ll either have a pending code for p1456 or not.

It seems to pass the test if ambient temps are high. If it’s cold out I’ll most likely see the code come up.

Ran a smoke machine through it but nothing showed any leaks.

Any suggestions?