My '88 Westy is experiencing the oft discussed 'hesitation at speed'.
Here is what I have observed.

The symptom is like someone cutting the electrical power to the motor
very quickly. However I noticed that this will stop *IF* you go to
full-throttle. Mid-throttle settings will produce the problem.

As far as my van the problem only shows up if:

* I've been driving continuously for more than 2 hours.
* The is an altitude is 1,000 feet or higher.

Turning the ignition off for 10 seconds then on again did not help the
problem.

Does anyone have any suggestions on what to check?

Todd
'88 Westy