The electronic throttle system is the key component of the intelligent control system of connected and automated vehicles (CAVs). Although CAVs are expected to be commercialized in the near future, in practice the disturbances and interruptions are not uncommon along the road. In this paper, we propose a new continuum model considering the traffic interruption probability and the electronic throttle opening angle effect. Based on the linear stability analysis, the stability condition of the proposed model is obtained. The KdV-Burgers equation of the new continuum model is further obtained in the nonlinear analysis. The density solution obtained by solving the above equation can be used to describe the evolution characteristics of traffic flow near the neutral stability curve. Results show that the traffic interruption probability and the electronic throttle opening angle effect has a considerable impact on the stability of traffic flow.