I have a 06 Pacifica 3.5 and I have had a p0420 code for about a year. So last week it started running really rough while idling and the exhaust fumes were really bad. Started smoking and could smell gas. Made it back home and thought the catalytic converter finally went bad so changed that only for it to run the same way. Anyone know if it could be a problem with the intake? Or a gas valve? Nothing is leaking underneath or making any usual noise.