96 cherokee stalls, sputters, and lost power

I have a 96 Jeep Cherokee that recently developed a scary quirk in which shortly after starting when applying the gas the cherokee seems to sputter and choke losing practically all power, it may seem like its going to die. Then 300-500 yds later it seems like the gas was finally applied and we're off. I took it to the garage but because no engine lights were on and after it little bout it drives normally there wasn't much they could do. We did a complete tune-up (spark plugs, wires, cap, etc), replaced the gas filter, cleaned fuel injectors, and changed the transmission fluid. These things seemed to alleviate the problem somewhat but not entirely. Any ideas?

Try having your catalytic converter checked out at a muffler shop sounds like it might be getting plugged up..... hope it works out for you