Yes, the nut has to come off. While it is the nut for the engine mount, it and the âKâ member do not support the engine. After you have the O2 sensors in take it for a long hard drive to get the cats good and hot. Its likely the cats got a bit contaminated from that old gas, long inactivity and frequent startups without really driving it. When I still lived I CA I found that a few good full throttle runs to redline immediately before taking to the smog station brought the numbers down somewhat.
H
