Alfa Romeo Repair: Engine out of tune, alfa romeo spider, alfa romeo

Question
!985 Alfa Romeo Spider 2.0  Car was running good.  One day I was driving onto on ramp of highway going to high RPM's in each gear as I picked up speed.  Then the car just "choked", had it in 5th gear with gas pedal to floor with no real response car slowed down from 55mph to 25 mph.  I thought maybe I revved it too high, but Iwas no way close to redline as a was going through gears.  I was able to get car to slowly pick up speed and get home, but she accelerates very slowly now, poor idle, and sounds like she's off timing.  I haven't checked anything yet and I'm not driving it.  Thought you might have some foresight to where I can begin.  I usually do most of the work myself on my cars.  This is my first Alfa so i'm just getting to know the car.

Answer
I suspect the catalytic converter guts have gone into the muffler.  This will happen if the engine is running too rich.
A quick check is to remove the oxygen sensor and hook up a low reading pressure gauge.  If you get more than 2 psi at 2000 rpm you have blockage in the exhaust system.