how to fix Cadillac Escalade T1XX (2021-Present) rough idle issue

Symptoms

• Engine vibrations noticeable at idle
• Check engine light illuminated
• Fluctuating RPMs at stop
• Poor fuel economy
• Possible engine stalling
• Increased emissions

Diagnostic Steps

1. Scan for error codes using an OBD-II scanner to identify any fault codes related to the engine.
2. Inspect the air intake system for any leaks or obstructions.
3. Check the condition and connections of spark plugs and ignition coils.
4. Evaluate fuel pressure using a fuel pressure gauge to ensure it meets manufacturer specifications.
5. Inspect the throttle body for carbon build-up or malfunction.
6. Examine the engine's vacuum lines for any leaks or cracks.

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, fuel pressure gauge, multimeter, cleaning supplies, and vacuum gauge.
• Disconnect the battery to ensure safety while working on electrical components.

2. Clean the Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner and a soft cloth to clean carbon build-up inside the throttle body.
• Ensure the throttle plate moves freely; if it is stuck, replace the throttle body as necessary.

3. Replace Spark Plugs and Coils

• Remove the engine cover if applicable.
• Disconnect the ignition coil connectors and remove the bolts securing the coils.
• Pull out the coils and replace the spark plugs using a socket wrench.
• Reinstall the ignition coils and connectors, ensuring they are seated properly.

4. Inspect and Replace Vacuum Lines

• Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
• Replace any faulty vacuum lines with OEM specifications to prevent air leaks.

5. Test and Adjust Fuel Pressure

• Connect the fuel pressure gauge to the test port on the fuel rail.
• Start the engine and monitor the pressure; it should match the specifications in the service manual.
• If pressure is low, check the fuel pump and fuel filter for blockages and replace if necessary.

6. Reconnect the Battery

• Once all repairs and inspections are completed, reconnect the battery.
• Clear any error codes using the OBD-II scanner.