The ornamental design for a portion of an automobile, as shown and described.
FIG. 1 is a front perspective view of a portion of an automobile of our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a right side elevation view thereof, the left side being a mirror image thereof except for the fuel door which is not present on the left side view;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a top plan view thereof.
The portion of the automobile in light contrast is environment and forms no part of the claimed design. The bottom view of the portion of the automobile forms no part of the claimed design.