I have a 92 F-150 Flareside 5.0 4x4 automatic, 189,000 miles; runs good, recently started hearing a banging noise around exhaust where left/right exhaust pipes intersect at catalytic converter. I got underneath while engine running and swear I could hear a banging noise bottom of oil pan or right behind oild pan at the exhaust pipes/catatylic converter. Any idea what I'm into to; truck turns over runs; thought I had a loose exhaust somewhere but it's tight. Ralph

 

maybe the catalytic converter substrate came apart and is bouncing around in there? maybe the flywheel? maybe just a heatshield?