Code 1406 :(

My cars fix engine light came on and I took it to jiffy lube they said I had a code 1406 I checked it out over the internet and found out that it deals with my engine's emission system he told me that same hoses were loose and he put them back on the same day at night the light came on again I took it back to them and they said its the same thing and they can't do anything about it so I searched the internet and found out what it means my downstream hose was unplugged or plugged (obstruction) or my catalytic converter was messed up and the accumulation of pressure is unpluggin the hoses --- I have a rattling noise when I speed up plus my car is having difficulty increasing speed so do you think I need a new catalytic converter? Or what is the problem with my car.