Got the 0420 code, O2 sensors checked out okay, both on OBDII and with an ohm meter. Less than 50 degrees temperature difference between cat in and cat out. No lack of power, but fuel economy had slipped by about 10% over the past 50,000 miles and the exhaust manifold on the 2.4 had the universal crack between cylinder 2 and 3. Replaced the cat and manifold. Code didn't clear within 75 miles so I reset it. 200 miles later it again threw a P0420 code. Front part of cat housing temperature after warmup is 309F. Outlet end of the housing is 204F. No lack of power. No change in fuel economy. O2 sensors still OK on OBDII. Haven't resistance tested them again. Ideas?
have the same problem?
Sunday, October 11th, 2020 AT 9:55 PM