That is an evap emmissions code - wont release vac here is fords description
P1450 - Unable to Bleed Up Fuel Tank Vacuum Monitors the fuel vapor vacuum and pressure in the fuel tank. The system failure occurs when the EVAP running loss monitor detects excessive fuel tank vacuum with the engine running (but not at idle). Blockages or kinks in EVAP canister tube or EVAP canister purge outlet tube (between fuel tank, EVAP canister purge valve and EVAP canister)
Fuel filler cap stuck closed (no vacuum relief)
Contaminated fuel vapor elbow on EVAP canister
Restricted EVAP canister
CV solenoid stuck open (partially or fully)
Plugged CV solenoid filter
EVAP canister purge valve stuck open
VREF circuit open (harness near FTP sensor, FTP sensor or PCM)
Damaged FTP sensor
THat being said I would ck the canister vent solenoid and hose[attached to evap canister] for an obstruction. you should be able to blow through the valve and hose freely.