Symptom Diagnosis

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in appropriate BASIC DIAGNOSTIC PROCEDURES article and appropriate SELF-DIAGNOSTICS article were performed before diagnosing a symptom. Following symptoms are available for diagnosis:

• ROUGH OR ROLLING IDLE, STALLS, MISSES, HESITATION OR SURGE 
• HARD START OR LONG CRANK 
• NO START/NORMAL CRANK (ALT FUEL) 
• NO START/NORMAL CRANK (GASOLINE) 
• SLOW RETURN TO IDLE 
• FAST IDLE (DIESELS/RUNS ON) 
• LOW IDLE (STALLS ON DECELERATION) 
• BACKFIRES 
• LACK/LOSS OF POWER 
• SPARK KNOCK 
• POOR FUEL ECONOMY 
• EMISSIONS COMPLIANCE