why does my Volkswagen Golf MK7 (2015-2019) lose power on the highway?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Address Faulty Components

A. Replace Spark Plugs

• Remove the ignition coil cover using a socket set.
• Disconnect the ignition coils and remove them from the spark plug wells.
• Use a spark plug socket to carefully remove the old spark plugs.
• Install new spark plugs, ensuring they are gapped to specifications (typically 0.028 inches for MK7).
• Reinstall the ignition coils and cover.

B. Repair or Replace Vacuum Leaks

• Visually inspect vacuum lines for cracks and replace any damaged hoses.
• Use a smoke machine to find hard-to-detect leaks in the intake system.
• Ensure all connections to the intake manifold are secure.

C. Clean or Replace Air Filter

• Open the airbox and remove the old air filter.
• Inspect the air intake for debris or restrictions.
• Install a new air filter that meets OEM specifications.

3. Fuel System Inspection

• Connect a fuel pressure gauge to the fuel rail.
• Start the engine and check if the fuel pressure is within the manufacturer's range (typically 50-60 PSI for the MK7).
• If pressure is low, check the fuel pump and filter for blockages or failures. Replace if necessary.

4. Electrical System Check

• Test the battery voltage with a multimeter; it should read approximately 12.6V when off and 13.7-14.7V when running.
• If the voltage is low, test the alternator output and replace it if it fails the test.