Troubleshooting

If an engine does not run well, there are often several possible causes, depending upon the symptom. The more information you can gather about the vehicle, the symptom and its occurrence, the easier your troubleshooting procedures will be. Try to determine the following;

• What type of problem is it?
  
• misfire
  
• hesitation
  
• surging
  
• lack of power
  
• other
  
• When does it happen?
  
• during acceleration
  
• during deceleration
  
• during steady throttle
  
• when stopped
  
• under a heavy load
  
• all of the time
  
• Under what conditions does it occur?
  
• when the engine is cold
  
• when the engine is hot
  
• at all engine temperatures
  
• in neutral
  
• only in one gear
  
• at what rpm
  
• sporadically
  
• only in the rain or wet conditions
  

• How did the problem develop?
  
• all at once
  
• it got progressively worse over time
  
• It started after an accessory was installed (air filter, exhaust, etc.)
  
• it started after work was performed on the engine
  
• Has anyone else worked on the vehicle?
  
• are they a qualified technician
  
• were they doing regular maintenance
  
• were they making repairs unrelated to the problem
  
• were they trying to diagnose the problem