What you are describing is a cylinder misfire. Misfires can be caused by many things. However, the first step would be to change the rotor, distributor cap, wires, and plugs. Unless you are certain that they were changed recently.
As far as mounts, if they were broken you would have constant vibration in the car during idling. If this is the case, you can check them visually.
Vinamg
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