As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MOMENTARY ENGINE ROUGHNESS/VIBRATION/ LOSS OF POWER. PILOT REPORTED:"ON TAKEOFF OUT OF LVK AT 600 AGL THE ENGINE LOST TOTAL POWER FOR A MINIMUM OF ONE SECOND. AFTER THE LOSS OF POWER THE ENGINE IMMEDIATELY CAME BACK. I ENTERED THE TRAFFIC PATTERN AND DISCONTINUED THE FLIGHT." FUEL SERVO REPLACED