98 Subaru Legacy GT, engine runs rough when hot

[superdav]

My 98 Legacy AWD wants to die after it’s been running for about 30
minutes. It runs fine when it’s first started but then out of the blue
it just starts chugging. I replaced the plugs and wires, could it be
the catalytic converter?

 

[Carl 1 Lucky Texan]

My 98 Legacy AWD wants to die after it’s been running for about 30
minutes. It runs fine when it’s first started but then out of the blue
it just starts chugging. I replaced the plugs and wires, could it be
the catalytic converter?

I suppose a LOT of things 'could' be the problem in a '98 .

You don't mention any check engine light/OBDII codes . If the light is
not on, I suppose the Engine Temp. Sensor could be bad. Basically
keeping the car in 'choke' mode even after it has warmed up. That may
not throw a code/light the CEL.

Carl