This is the first time my vehicle has failed smog with an emmission problem in {ppm} reading max of424 meas. 489 ave27 my question where do I look first any ans.

. Change the spark plugs with the same Motorcraft plugs that originally came in the car.

. Start using full synthetic 5W-30 engine oil (e.g. Mobil 1). Change oil and premium filter every 6,000 miles or 6 months, whichever comes first.

. Check for any hard or pending codes.

. Clean the throttle body and throttle plate.

. Ensure the MAF Señor and Oxygen Sensors are operating properly.