EVAP Leak 2004 CR-V

I have a 2004 Honda CR-V. The check engine light came on. I was told it was due to the gas cap not being on tight. The dealer ran a diagnostic and said that was the problem. A week later the light is still on. A diagnostic says there is an EVAP leak. The dealer has replaced the Purge Control Valve and there is still an EVAP leak. They have had the car for over 2 days, and cannot seem to find it. Was the Purge Control Valve replacement necessary or am I being taken by the dealer?

Instead of them just replacing parts of the EVAP system to find the leak, they should be using a smoke machine to locate the leak. This is one of the main reasons these smoke machines were created.

Tester

Did they reset the Check engine light? I have had this problem often because my wife never tightens the gas cap after she fills up. If it is just the cap, it will take a week of driving but the car computer will actually remove the failure if it detects no further problems with the gas cap.

Yes, They did a smoke test and then replaced the Purge Valve Control. But they said there is still an EVAP leak. They have had the car for 2 1/2 days. Is it really this difficult?