If the problem is the catalytic converter, of course this would be the right solution. A catalytic converter should only be replaced if it is operating inefficiently or not at all. There are tests that can be performed on a catalytic converter to determine whether or not it needs to be replaced. The fuel evaporative system is designed to hold the hydrocarbon vapors and introduce them into the engine to be burned. The hydrocarbon molecules attach themselves to the charcoal contained in the canister.
Gas caps are also part of the fuel evaporative system.
They prevent pressurized vapors from exiting the fuel tank through the filler neck. The gas cap pressure test is used to verify the condition of the gas cap. This system regulates air temperature flow into the engine. The phase-in period for the thermostatic air cleaner system inspection ended May 31, 2000. During the phase-in, system failures were advisory.