pull the o2 sensor & drive the car,if it runs much better, it has a clogged cat,, this allows the exhaust gas to escape thru the hole ,, your neighbors may not love you.
is the cat welded on or bolted
does the car seem to run strong ??
make sure the spark plug wires are not grounding on metal or touching,running along together
do not use a bosch 02 sensor
is this a V6 or a duke 4 cylinder
[This message has been edited by uhlanstan (edited 01-29-2014).]