cutlass supreme. Car chugs and looses power when gas pedal is pressed half way.

The simplist of things can cause this, i would replace the fuel filter it sounds to be clogged and is starving the motor for fuel.

could be , one fuel pump filter, vacuum hoses might be loose, PVC valve clogged, fuel filter, gap in spark plugs I had the same problem and I tore down the engine and saw that my spark plugs were not gap right, and one of my vacuum hoses came off of the map sensor, also had to change the head gasket because of oil and coolant in the cyclinder

Sorry guys, but I think you're all very close, but to me it sounds like a plugged up catilist converter. It exaust well enough at idle and non p[ower mode, but it wont leave enough room for above average exaust. Disconect it and try without it, and no great expense spent for repairs.