Catalytic Converter(Dodge ram van still boggy on acceleration up hills)

Hi Car talk; thankyou for your help so far; this was my Initial question;

Hi CAr Talk; I have a question about my 2003 dodge ram van;(1500 series) the van runs really good except up hills it seems like it looses its ummmph(almost like it might conk out) anyone have any experience with this challange? thankyou for your time; great show on the radio Frank;

I changed the spark plugs; but still boggy; is there a way to check the Catalytic Converter; thankyou; thinking it might be on the back end,