Ford 2003 Mustang Workshop Manual page 3062

Is the hose pinched or kinked?
A17 CHECK VACUUM CIRCUIT CONNECTIONS
Check each vacuum hose connection to determine if it is partially
connected or disconnected.
Is a vacuum hose disconnected or partially connected?
A18 CHECK THE VACUUM HOSE
Disconnect the suspect hose.
Plug one end of the hose and attach a vacuum pump to the other
end. Check for a leak in the hose.
Does the vacuum hose leak?
A19 CHECK THE VACUUM CONTROL MOTOR
Disconnect: Vacuum Control Motor.
Check the vacuum control motor for leaks with a vacuum pump.
Yes
RECONNECT the
hose. TEST the system
for normal operation.
No
GO to A18 .
Yes
REPAIR or INSTALL a
new hose. TEST the
system for normal
operation.
No
GO to A19 .
Yes
GO to A20 .
No
INSTALL a new
vacuum control motor.
TEST the system for
normal operation.