my Alfa Romeo Giulia 952 (2016-Present) hesitates when accelerating, what could it be?

Symptoms

• Hesitation or stuttering during acceleration
• Engine misfires or rough running
• Check engine light illuminated
• Decreased fuel efficiency
• Unusual engine noises during acceleration
• Poor throttle response

Diagnostic Steps

1. Scan for error codes using an OBD-II scanner to identify any stored fault codes.
2. Inspect the air intake system for any blockages or leaks, ensuring proper airflow to the engine.
3. Check fuel pressure using a fuel pressure gauge to confirm if the fuel pump is operating correctly.
4. Examine spark plugs for wear or fouling, which can lead to misfires.
5. Inspect ignition coils for proper function and signs of damage.
6. Review the mass airflow (MAF) sensor readings to ensure accurate air measurement.
7. Check the throttle position sensor (TPS) for proper voltage and functionality.

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plugs

• Remove the engine cover if applicable.
• Disconnect the ignition coil connectors.
• Remove the ignition coils using a socket set.
• Unscrew and remove the spark plugs using a spark plug socket.
• Inspect spark plugs for wear; replace if necessary with OEM specifications.
• Reinstall new spark plugs and ignition coils, ensuring proper torque (typically 13-15 lb-ft).

3. Check and Replace the Fuel Filter

• Locate the fuel filter in the fuel line.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect fuel lines from the filter using a fuel line disconnect tool.
• Remove the old fuel filter and install the new one, ensuring the flow direction is correct.
• Reconnect the fuel lines and reinsert the fuse to restore power to the pump.

4. Clean or Replace MAF Sensor

• Locate the MAF sensor in the air intake system.
• Disconnect the electrical connector and remove the sensor.
• Clean the MAF sensor using MAF sensor cleaner (do not use other solvents).
• If cleaning does not resolve the issue, replace the MAF sensor with an OEM part.

5. Test Throttle Position Sensor (TPS)

• Locate the TPS on the throttle body.
• Disconnect the electrical connector and use a multimeter to check voltage output.
• If the voltage readings are outside the manufacturer’s specifications, replace the TPS with an OEM part.