The tach instantly dropping to zero and coming back is a clear
electrical problem. It has NOTHING to do with the fuel, fuel pump, fuel
filter, plugs, plug wires, cap, or rotor. If the shop thinks it does,
you might need to go elsewhere. It is important to make note of the
symptoms each time things are going wrong as there can be more than one
problem. Was the tach going dead every time the cutting out occurred and
while the vehicle was till moving in gear? Do you have a manual or auto
tranny?

Unless the problem occurs constantly, a shop may either give up or use
the shotgun approach of replacing everything they can think off at your
expense until the problem is gone or you are gone.

As recent list traffic shows, some problems arise that are not easily
identified. Some turn out to be cheap to fix and others a little more
costly. The trick is finding it without buying too many needless new
parts. The main thing is to follow a set of tests, not that any will
point right away to exactly what is wrong. The tests should be designed
to divide the possibilities into groups, then eliminate whole groups to
quickly narrow the remaining possible causes down to where parts
replacement is not so open ended.

Mark

Gregor Brandt wrote:

> '86 Westy
>
> Well, after pulling the van apart and putting it back together again,
> electircally, it was running smoothly.  So I risked the trip from
> Winnipeg to Calgary (1400km).  First 100 km went fine, then the
> engine started die-ing again.  Tach going to zero, then coming right
> back up (read previous posts).  Turned around and got 40 km before it
> was happening all the time.  Van would start, then die immediately.
> My wife was not a happy woman.
>
> So, its towed and in the shop, whatever the problem is, I can't find
> it or fix it.   We'll see what the shop says.
>
> Gregor
>