if the cat is clogged it will cause your acceleration to dramatically decrease but it wouldnt cause the accelerator to stick...if it is the cat there is a dirt cheap way to fix the problem if you dont have to do emmisions test...get yourself a sawzall, a broom stick and a hammer plus all needed to fix the pipe
cut off the exhaust after the cat and stick the broom stick into the cat, beat it in with the hammer and wiggle it around. start it up to blow all the crap out, which is why i say broom stick and not just a stick because now you have a mess to clean up. dont let it keep running because it will get HOT. put pipe back together, problem solved
but once again, thats only if you dont have emmisions tests