Larry,

         Dunno if it will help diagnose your problem, but I've noticed (in
my '85) that when the system voltage is *low* , the tach will swing
*high*... maybe your alternator brushes are on the way out, or an
intermittent short somewhere is pulling the voltage down.

Tim

At 02:27 PM 5/7/2003 -0700, Larry H wrote:
>Good evening all -
>
>Hoping this rings a bell with someone:
>
>My tach periodically behaves erratically, swinging
>between zero to 4000 rpm while at a stop light. It
>calms down as the engine speed increases.
>
>BUT, there is a high probablity of a power loss
>occurring afterwards.
>
>The power loss is manifest in either of two ways:
>
>1. Running smooth, but down on power....like a
>temporary fuel filter plug or a timing retard.
>
>2. A complete shutdown. The wiring harness patch has
>moderated this (usually)to a hard stumble, then it
>runs Ok.
>
>Thanks,
>
>Larry Hensley
>'88 GL automatic (Acadia)
>
>__________________________________
>Do you Yahoo!?
>The New Yahoo! Search - Faster. Easier. Bingo.
>http://search.yahoo.com