Cold Start Fuel Injection Quantity A Lower Than Expected

Common symptoms

What you'll notice

• Check the fuel injectors for any clogs or leaks and clean or replace as necessary
• Inspect the fuel pressure regulator and ensure it is functioning properly
• Verify that the engine coolant temperature sensor is providing accurate readings and replace if faulty
• Examine and clean the air intake system, including the air filter and throttle body
• Test the oxygen sensors to ensure they are operating correctly and replace if needed

Common causes

Most likely first

1. Clogged fuel injectors
2. Faulty fuel pressure sensor
3. Malfunctioning fuel pump
4. Dirty or faulty Mass Air Flow (MAF) sensor
5. Oxygen sensor malfunction

How to diagnose & fix

Work through it in order

1. Difficulty starting the engine in cold weather
2. Rough idling or stumbling engine at startup
3. Poor acceleration or lack of power when accelerating
4. Engine misfires or stalls during operation
5. Increased fuel consumption