On Deceleration

Perform the following in order:

• Check IACV-AAC valve and IACV-air regulator. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Perform power balance test.
• Check fuel injector operation. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Check ignition spark.
• Check fuel pressure. See BASIC TESTING article in the ENGINE PERFORMANCE Section.
• Check oxygen sensor. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
• Inspect ECM harness connector for damaged pins or poor connection.
• Check ECM power supply and ground.
• Replace ECM with known good unit.