As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED ODOR OF GAS WHEN APU WAS TURNED ON. ODOR WOULD GO AWAY WHEN PACK 1 WAS TURNED OFF. MAINTENANCE INSPECTED AND PERFORMED OPS CHECKS OF PACKS 1 AND 2. OPS CHECKED GOOD. COULD NOT DUPLICATE DISCREPANCY. THE ACFT WAS RELEASED FOR SERVICE.