Direct Answer • Key Takeaway
Uneven Idling and Vibrations Is a Major Warning Sign That Indicates Faulty Spark Plugs. the Car Engine Will Run at Lower Rpm During Idling and Runs Smoothly Without Any Noticeable Vibrations or Sound. Failing Spark Plugs Can Result in the Engine to Become Rougher and Produce Vibrations When Left at Idle Speeds.
