I don't know what you mean by "chugging", the only thingI knows that cuogs is a syeam locomotive. Has any testing done? As Uncle Bill said, with all the miles it is time to change the cat or at least do a back pressure test.

 

I had the same problem with my 94 v6. I replaced the spark plugs and wires with some bosh platinum2's and msd 8.5 mm wires. The chug was gone.