1999 dodge ram 2500 5.9 360

plug wires suck and tend to arch around screwing sensors up.

you need to check plenum gasket as mentioned thru the TB, if their is oil its popped.

http://www.forabodiesonly.com/mopar/showthread.php?t=233963

Cats on these trucks collapse on themselves and really kill the motor

buy some good plug wires or good phenolic separators and see where you end up.