As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ACFT HAD JUST DEPARTED WHEN CREW HAD FLUCTUATING PRESSURE ON THE NR 2 ENGINE WHICH HAD JUST BEEN REPLACED. IN CONSULT WITH MOC IT WAS DECIDED TO RETURN TO DEPARTURE AIRPORT. R & R NR 1 SDCA IAW AMM 31-55-34, PERFORMED MINIMUM IDLE LEAK CHECK, NO DEFECTS NOTED.