my Cadillac Escalade's engine runs rough when warm what could be the cause

Symptoms

• Check engine light illuminated
• Rough idle when warm
• Loss of power during acceleration
• Increased fuel consumption
• Engine stalling at low RPM
• Unusual engine noises (e.g., knocking or pinging)

Diagnostic Steps

1. Scan for error codes using an OBD-II scanner to identify potential diagnostic trouble codes (DTCs).
2. Inspect the ignition system, including spark plugs, ignition coils, and wires for wear or damage.
3. Check fuel pressure using a fuel pressure gauge to ensure the fuel system is functioning properly.
4. Verify the operation of the mass airflow sensor (MAF) and clean or replace it if necessary.
5. Inspect the throttle body for carbon buildup and clean it if required.
6. Check for vacuum leaks in hoses and intake manifold gaskets.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the engine cover if applicable.
• Disconnect the ignition coils from the wiring harness.
• Remove the ignition coils using a socket wrench.
• Inspect spark plugs for wear; replace if necessary (use OEM specifications for gap).
• Reinstall new ignition coils and reconnect wiring harness.
• Reinstall the engine cover.

3. Fuel Pressure Check

• Tools Required: Fuel pressure gauge
• Locate the fuel rail and attach the fuel pressure gauge to the test port.
• Turn the ignition key to the "On" position (do not start the engine) to check fuel pressure.
• Compare the reading with manufacturer specifications; replace the fuel pump if it’s below specification.
• Disconnect the gauge and resecure any fuel lines.

4. Throttle Body Cleaning

• Tools Required: Throttle body cleaner, soft cloth
• Remove the air intake duct connected to the throttle body.
• Spray throttle body cleaner inside the throttle body while opening the throttle plate manually.
• Wipe away carbon buildup with a soft cloth.
• Reassemble the intake duct.

5. MAF Sensor Inspection

• Tools Required: Torx screwdriver, MAF cleaner
• Disconnect the MAF sensor electrical connector.
• Remove the MAF sensor from the intake duct.
• Clean the sensor with MAF cleaner according to manufacturer instructions.
• Reinstall the MAF sensor and reconnect the electrical connector.