171. The following are major defects:1° an engine that does not return to idle when the accelerator is released;
2° a fuel leak other than sweating along the fuel system;
3° a tank that leaks, excluding oozing, so poorly fixed that it could break loose or that has no cap; and
4° a leakage of exhaust gases from a gasoline or gaseous fuel engine under the passenger compartment where the floor is perforated or in the engine compartment.