To address the road noise issue in a pickup truck prototype, the wheel center force loading method is employed to simulate and optimize the vehicle road noise. The wheel center acceleration responses at specific speeds are measured experimentally, and the transfer functions from the wheel centers to the measurement points are simulated and calculated. Using inverse matrix theory and principal component analysis (PCA), 24 linearly independent principal components of the wheel center forces are obtained and applied to the full-vehicle simulation model, yielding road noise results that closely matched the experimental data. Combining with the concept of transfer path analysis (TPA), a rapid diagnostic method for identifying road noise peaks is proposed, enabling efficient localization of problem areas. The optimization results of the pickup truck chassis bushing stiffness demonstrated the effectiveness of the proposed diagnostic and optimization process.