James:
I had the same problems you are citing, even after a Bob Donalds Engine
rebuild.  The way I fixed the problem was to completely replace the engine
wire harness. The harness connects the ECU to all engine components. The
result is no more hesitation, bucking, etc. Just a fine running engine,
finally.

Prior to undertaking that project I thoroughly cleaned all connections,
ground points, changed the O2 sensor, etc., all to no avail. Replacing the
harness was not a particularly difficult job.
Good luck.
John S
'89 Carat

----- Original Message -----
From: "James" <tornadored@HOTPOP.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, November 05, 2002 3:12 AM
Subject: hesitation, bogging, rough idle

> The archives have been helpful in pointing me in the right direction, but
I
> though I'd ask about my specific symptoms ('90 2.1L):
>
> Rough idle (occasionally will barely stay running when cold)
> Hesitation/loss of power/bogging under acceleration (sometimes need to
back
> way off on the throttle to accelerate w/ out bogging)
>
> It used to be that when the van was cold, it would always start,
accelerate,
> and drive fine.  Then, after, say, a 30 min fwy commute, I would come to a
> stop and notice the rough idle and poor acceleration.  But now, it happens
> even when cold.
>
> It always cruises fine (or at least the symptoms aren't noticeable at
> speed).  I'm aware of the "intermittent syndrome," but from the
description,
> it seems like this problem usually causes sudden power loss while
cruising,
> and can be temporarily cured by turning the car off.  Not so w/ my van.
>
> This problem seems to recur/disappear in long intervals.  That is, it will
> run fine for perhaps several weeks, than misbehave for several, with only
a
> few occasions in between that oppose the trend.
>
> What would be the most likely problems and how can I test?
>
> Thanks,
>
> James
> 90 Carat