Subaru 2002 IMPREZA Service Manual page 1511

Symptom
6. Surge
7. Spark knock
8. After burning in exhaust system
*1: Check ignition coil & ignitor assembly and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Ensure the secure installation.
*4: Check fuel injector, fuel pressure regulator and fuel filter.
*5: Inspect air leak in air intake system.
*6: Adjust accelerator cable.
GENERAL DIAGNOSTIC TABLE
Problem parts
1) Pressure sensor
2) Mass air flow and intake temperature sensor
3) Engine coolant temperature sensor (*2)
4) Crankshaft position sensor (*3)
5) Camshaft position sensor (*3)
6) Fuel injection parts (*4)
7) Throttle position sensor
8) Fuel pump and fuel pump relay
1) Pressure sensor
2) Mass air flow and intake temperature sensor
3) Engine coolant temperature sensor
4) Knock sensor
5) Fuel injection parts (*4)
6) Fuel pump and fuel pump relay
1) Pressure sensor
2) Mass air flow and intake temperature sensor
3) Engine coolant temperature sensor (*2)
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
EN(TURBO)-351
ENGINE (DIAGNOSTICS)