Here's what's going on (aside from the coolant issue in my other post):

She's been getting 15 mpg in mixed driving over the last month. I
checked around her and saw that the J-pipe in the exhaust, the one that
houses the OX sensor, had a hairline crack. So I disconnected the OX
sensor. Now, 11/2 weeks ago the J-pipe got replaced. I  reconnected the
OxS  and went to have her smogged. Passed (in California). But I kept
on getting poor fuel mileage, about 15 mpg. No other problems except
coolant whizzing out of the water pump. Ran beautifully and powerful.
So I went and exchanged the OxSensor, checked visually for all the
vacuum hoses and tightness,  all connectors, all ignition wires etc.
Went for a ride with the new OxS yesterday and she ran worse, poor
idling, would not go past 4000 rpm once warm, in any gear, accompanied
with some occasional bucking.
I now just replaced the rotor and cap, but that only worked until she
was fully warmed up again. Needless to say I don't have the OxS
connected anymore at all.
This is a rebuilt/resealed motor with about 3000 miles on it.

My plan is to

- check and replace spark plugs, do compression test
- check coil
- check ignition wire resistance
- try to perform a test on the AFM (per Bentley)
- try to test distributor
- call Autotrader :(

I am pretty sure it is a ignition problem vs. fuel problem Not 100%
though. The fuel filter is about 18 months old, the air filter is 6
months old. The fuel pump and fuel regulator are 3 years old. How would
I be able to check the injectors, apart from taking them out and see
that the spray is cone shaped??? Could my exhaust be blocked from a
disintegrating cat??
She runs perfect when cold, say for about 2-3 miles in city traffic,
and she'll happily rev past 4000 rpms. Once warmed up this is no more
so.

I am gonna go and piss off into the archives for couple hours,
meantime, any and all help is greatly appreciated.

Matthias

'84 WBX Man Wolfy in Los Angeles, CA