Diagnostic states 3rd cylinder mis fire - Marquis Mercury Cars & Trucks

Hello, Depending on the Year of the car, the cars that had a sparkplug with a remote coil, you could have a bad sparkplug wire or a bad coil-pack or a bad sparkplug. For newer cars, the coil is attached to the sparkplug directly on top.

For those newer designs, the coil would need to be tested for that cylinder. Using an Ohmmeter, with 1 lead on top and the other on the tip which touches the sparkplug, it is a 10,000Ohm resistance.

Accessing the sparkplug coil is different for several engines. You may have to remove the Intake manifold to reach the coil and you may need to remove part of the fuel rail to remove the Intake manifold. Switching out a plug or coil is easy once you can get to it.

You can have your scans done free at Autozone, Oreillys, or Advance autoparts and they will clear the problem codes once you replace parts. I hope this Solution is very helpful to you.