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Realistically experiencing the sound and vibration data through actually listening to and feeling the data in a full-vehicle NVH simulator remarkably aids the understanding of the NVH phenomena and speeds up the decision-making process. In the case of idle vibration, the sound and vibration of the idle condition are perceived simultaneously, and both need to be accurately reproduced simultaneously in a simulated environment in order to be properly evaluated and understood. In this work, a case is examined in which a perceived idle quality of a vehicle is addressed. In this case, two very similar vehicles, with the same powertrain but somewhat different body structures, are compared. One has a lower subjective idle quality rating than the other, despite the vehicles being so similar. An NVH vehicle simulator was used to compare the sound and vibration characteristics of the two vehicles back-to-back in a realistic vehicle environment in order to understand the difference in the subjective rating. With the ability to control the various specific sound and vibration stimuli, the reason for the difference of subjective rating between the vehicles became apparent rapidly. Further, the interaction of sound and vibration and the resulting effect on human subjective perception is explored, which emphasizes the importance of having both sound and vibration accurately reproduced and controlled for such simulations. Objective Measurements Sound and vibration measurements were acquired on both vehicles under several operating conditions. Vibration measurements were acquired utilizing seat-pad accelerometers on the seat base and seat back, and also at two locations on the steering wheel. Acceleration was also measured at the floor-pan/heel point. Tri-axial acceleration was measured at all locations. The accelerometers on the steering wheel were located such that both translational and rotational vibration could be resolved.