Subaru 2002 IMPREZA Service Manual page 946

ENGINE (DIAGNOSTICS)
Symptom
13. Poor engine revving
14. Remarks
A*: Including ECM ground circuit
B*: Check hoses.
GENERAL DIAGNOSTIC TABLE
1) Pressure regulator
2) Pressure sensor
3) Engine coolant temperature sensor
4) Throttle sensor
5) Fuel pump
1) ECM power supply
2) Pressure sensor
3) Pressure regulator
4) Idle air control solenoid valve
5) Air leak in air intake system
EN(w/oOBD)-112
Problem parts Priority
A
B
B
B
B
A*
B*
B*
B*
B*