Meow? (NAC but VAG diagnostics)

[tihol tiholov]

Patient: '99 VW NBeetle, 229K kms, 2.0, sparkplugs are about 30K, wires about 4-5 weeks old, both OEM. 
Cold-like symptoms turing into pneumonia - cough, sneeze, sputter, @ initial start smooth idle, then after a couple of seconds misfiring and even stalling, no power, impossible to drive except downhill.
All this went on and off for a few months, lately progressively worse to almost lethal.  
On Sun used VAG-COM to turn off CEL or MIL, if you will, codes were System too lean and some intermittent misfiring.  Irregular running but was drivable on my 1.5-acre gravel driveway.  Smelled hot like a kitty.  On Mon taking off downhill, made it till the mountain bottom, no power, stopped, trying to drive, CEL blinking and smells like the kitty.
So, I think, if it smells like a cat ... it gotta be one.  VAG-COM saved random and particular cyl. misfiring - 3 and 4 this time, 2 was there before.  OXS shall be renewed as it's more than 100K but doubt it it would make it so sick.

MAC - on my '88 Typ 89 the kitty was caught plugging before the 200k kms mark by an alert exhaust tech, so no BTDT of my own.

Just wonder what other people's experiences with a  plugging cat were.  Also, anything else to blame the car flue on?

Thanks all and merry spring motoring.
Tihol
     

TT