I have a 2002 mercury sable. When I am idling I can feel this random stutter. I can only feel it when I am stopped or in park, and it seems to be random. Sometimes it will happen a couple times in a row, sometimes just once. There are no check engine codes showing. Any ideas how to narrow this down?

 

Does the vehicle still have the problem or did you correct it?

 

Still has the problem. Hoping to tinker with it this weekend.

 

Sometimes a reminder of the basics turns the light on upstairs at least in my case.
When were the plugs last replaced , if possible were they Motorcraft, do you know which engine you have in there what kind of maintenance has been done say in the last 6 months.