Diagnosis By Symptom

NOTE: If the vehicle exhibits any of the following symptoms and an emission component is suspect, be sure to visually inspect the following before any tests are performed:
1. Vacuum hoses for leaks, splits, kinks and proper routing.
2. Ignitions wires for cracking, hardness and proper connection at the distributor and sparkplugs.
3. Wiring harnesses for proper routing and connection.

Determine if any fault codes are stored in the ECM. Correct any faults indicated before proceding.

SYMPTOM:

ROUGH IDLE
Check:
1. EGR System
2. PCV System

FREQUENT STALLING, WARM ENGINE
Check:
1. EGR System

ROUGH RUNNING OR MISFIRE
Check:
1. EGR System
2. PCV System

FAILS EMISSION TEST
Check:
1. Catalytic Converter
2. Evaporative Emission Controls
3. EGR System

LOSS OF POWER
Check:
1. Catalytic Converter
2. EGR System