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.