The fix at this point seems to be holding up after 150 miles as there has been no reemergence of the code. This weekend, I'll work the other code a P0455 so I can get on with SMOG certification.
I'm thinking I'll get under the car to inspect all rubber hoses. I will replace some new silicone hoses I put in when I swapped motors. If the hoses are intact, I may have to being it in as I don't know how to test the purge or vent valves.
