Hi,

I had similar symptoms with an old Toyota Celica.  It was a broken spark
plug wire.  All the while it was "easy" (ie:  mixture rich) for the plug
to fire, it did.  As soon as I put my foot into it, the resistance to
the spark (presumably because the mixture was leaner) got more, and it
sparked from the break in the plug wire to the engine block leaving the
engine firing on three cylinders and a very noticeable "bog".  Ease off
on the throttle and everything ran fine.  I got great gas mileage while
I was trouble shooting the problem :-)

The only difference is that mine ran fine when the engine was cold
(automatic choke on), but as soon as it warmed up the symptoms showed
up.  Of course, it was winter in Canada, so "cold" meant REAL COLD.

The solution was to snip off the broken part of the plug lead, reinstall
and all was golden :-)  I was in university and a whole new wire set was
too expensive.

It was incredibly hard to troubleshoot and thus has remained ingrained
in my brain.

Good luck!

Cheers,
Steve

Aaron wrote:
> I am about to dive into troubleshooting a problem with my '87 westy. It =
> seems that after giving it more than 1/4 throttle while under load in =
> any gear, I lose all power. If I let off the gas pedal, it comes back to =
> life. However, I can rev it freely when it's in neutral, so it seems to =
> be associated with load. It also does this whether warm or cold. I'm not =
> sure where to start, but I figured I would start with the buzzing fuel =
> pump and go from there. It seems if it were a fueling issue, it would be =
> more of a sputter, not a sudden cut-out like it is.=20
>
>  It seems like there are so many routes one could take. What would you =
> do?
>
> Thanks!
> Aaron
> '87 Westy
>