Cliff, I had a similar problem with my '84 and I was living with it until I
could get a new exhaust system in along with new O2 sensor.  One afternoon,
the engine wouldn't start when I needed to go out.  I had to do something,
and my first check was the distributor rotor and cap... They were Brand X
and not Bosch, and were really in bad shape.  I cleaned them up enough to
get going, but it took new cap and rotor to get things right.

John
----- Original Message -----
From: Cliff Ober <cdo9@CSI.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, June 29, 1999 2:26 PM
Subject: 84, rich running, help request...

> I have an '84GL (190k miles) with a newly rebuilt engine. It ran
beautifully
> before tear-down, but leaked at the heads.
>
> Since re-installing it, I've had loads of trouble with extremely rich
> running, stumbling, poor idle, small backfires in the exhaust when
shifting,
> and high gas consumption. I've been through the Bentley checking things
and
> I've found only one problem. That was a stupid move on my part when I
> replaced the O2 sensor wire connector and didn't realize it was a co-ax
> wire - I just crimped on a new one. Fixing that improved things somewhat,
> with good idle and better gas consumption.
>
> I'm still seeing stumbling (the AFM capacitor fix has been done, as well
as
> shifting the AFM internal circuit so the wiper follows a new path on the
> variable resistor) and some small backfiring during shifting. With the O2
> sensor (its new) unplugged, things get even better, but are not gone
> altogether. I've spent tons of time checking things on this, but I'm at a
> loss as to what's causing the problems. Can anyone out there make some
> suggestions as to what's causing this?
>
> Many thanks in advance...
>
> Cliff Ober