Manifold flange had cracked bolt holes. Basically this was used to connect it to reduce exhaust and sound power. Obviously spending a few hundred dollars and a few hours of work would be ideal, but this is a 20-year-old work truck. It still works great. I also had an oxygen sensor/engine fault check before I bandaged it. The reading returned to normal and the major fault changed to a minor fault/check engine, the light went out by itself.