The ornamental design for an adjustablevehiclecover, as shown and described.
FIG. 1 is a right side and back side perspective view showing the adjustable vehicle cover of the present application and the design on the left side perspective view is the same as the right side perspective view;
FIG. 2 is a front side and right side perspective view showing the adjustable vehicle cover of the present application;
FIG. 3 is a front side and right side perspective view showing the adjustable vehicle cover of the present application;
FIG. 4 is a front side and right side perspective view showing the adjustable vehicle cover of the present application;
FIG. 5 is a front side and right side perspective view showing the adjustable vehicle cover of the present application; and,
FIG. 6 is a right side and back side perspective view showing the adjustable vehicle cover of the present application and the design on the left side perspective view is the same as the right side perspective view.