i think u should take it to the honda dealer and have them look at it instead of a regular shop. at least just to get diagnostic by honda. also the problem maybe got worse because u waited so long. usually the O2 sensors die first then if u dont change the O2 the catalytic converter follow next. whatever u do i aggree with the above, u should definetly get a second or third opinion. 186k sweet another reason to buy a honda.