Engine Backfires

If fuel ignites in intake manifold or exhaust system and makes a loud popping noise, check the following items:

• Ensure sufficient secondary spark is available.
• Ensure ignition timing and controls are working properly.
• Check for faulty spark plugs, spark plug wires, distributor cap and rotor.
• Check for proper spark plug wire routing.
• Check for low compression.
• Ensure valve timing is correct.
• Check fuel pressure.
• Check EGR and solenoid operation.