Berryman Intake Valve & Combustion Chamber Cleaner (part #2611) can help with catalytic converter problems by helping to optimize the combustion process.  However, you likely need to address fuel injector cleanliness, too.  We recommend using Berryman B-12 Total Fuel System Clean-Up (part #2616) in the gas tank at a concentration of 1 fl oz/gal in order to thoroughly clean fuel injectors.  As a bonus, 2616 will also help with intake valve deposits in older style engines as well as combustion chamber deposits.