I had similar symptoms, and the capacitor fix seemd to help a little also. After
capacitor fix, extra grounds, adjusting AFM wiper arm, etc, my problem was
eventually cured completely by examing the ECU - I found several cracked solder
joints. Heated & re-flowed the solder, and all has been great for 2 years now. I don't
know how common this is, but it is fairly simple to check for. Use standard
precautions when working with ECU re: static electricity of course. (mine is an '88
also).

On 16 Jan 2005 at 16:11, Warren Lail <wlail@OU.EDU> wrote:

> Hi all,
>
> Maggie and I made a safe and fun trip to New Mexico (1200 miles roundtrip) and
> Bill Bones performed well, sort of...
>
> The dreaded bucking syndrome began so I stopped and soldered in a 15 volt 22
> microfarrad tantalum capacitor that I got from listmember Tom Miller.  I
> connected the positive side to number 2 and the negative side to number 4.
> Interestingly, the idle that had always surged, was now stabilized.  The next 50
> miles were a joy.  No bucking at all.
>
> However, after about an hour on the road, just when the bucking normally begins,
> I got a diluted version of the same thing.  It appears that the capacitor stores
> energy or something like that, and when the system needs it it is returned (not
> sure about this).  The result was that instead of a bucking jolt like I normally
> get, I got a slow loss of power, and then a return surge.  It is as if the
> capacitor is almost powerful enough to remedy the situation, but not quite.
>
> On the return trip, I got behind the bus and smelled the exhaust.  It seemed to
> have that smell associated with a lean engine.  Not wanting to burn anything up,
> I disconnected the capacitor.
>
> Of course, the original bucking returned, as did the high idle (1800 rpm after
> coming off the Interstate). The high idle is never a problem around town.  It
> only occurs after extended driving on the Interstate, and accompanies the
> bucking behavior.
>
> Several questions:
>
> 1.  Is the capacitor really a fix or just a band-aid?
> 2.  If it is a fix, what did I do wrong?  If a band-aid, what is the real cause
> and how can it be remedied? 3.  Will a new AFM solve the problem? 4.  Is the
> factory pigtail a better fix (albeit a more expensive one)?
>
> As always,  thanks for your help.
>
> Warren Lail
> 88 Westy "Billy Bones"
>

--
Shawn Wright
I.T. Manager
Shawnigan Lake School