A good cat will fix most emission issues that would be a concern on an idle test. My old 1g past with flying colors with 60psi in one cyclinder. And my dads old jimmy just pasted with so much oil leaking thru the valve seals that he could not see thru his back window when he started up. I dont think the slightly rich idle will fail.. The cat will even it out. But either way.. The retest is the same price.