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We Service and Repair All Mercury Cars

2010 Mercury Mariner


Mercury Mariner

Service Date
Services Performed
  • Confirmed both of the customers concerns. We reset the oil maintenance light and scanned the vehicle for codes. At this time three codes were stored in the computer P0300 (random cylinder misfire detected) P0301 (cylinder #1 misfire detected) P0303 (cylinder #3 misfire detected) P0316 (misfire detected on start up) Performed initial diagnostic testing by watching the misfire counter on the scan tool. At this time the only cylinder misfiring was the #1 cylinder. We then switched the #1 and #2 cylinder ignition coils to see if the misfire would follow. The misfire stayed on the #1 cylinder, we then switched the #1 and #2 cylinder spark plugs and the misfire stayed on the #1 cylinder.
  • Performed compression test on all four cylinders and they tested as follows #1-50PSI #2-165PSI #3-165PSI #4-165PSI We then performed a wet compression test on cylinder #1 to verify a valve or piston ring issue and the pressure stayed the same which means that there is an issue with either one of the valves, one of the camshafts, or there is a hole in the piston. Our recommendation at this time due to the mileage on the vehicle would be to replace the engine with a used engine rather than to remove the cylinder head and make repairs.
John W. gave our service a 5 star review on 3/7/2020
2010 Mercury Mariner 2020-03-08T22:01:04+00:00