I have an '88 Westy with 164K miles and am having a Vanagon syndrome variant problem.
I'd be open to any suggestions along with any quick ways to determine if engine cut-outs are fuel or ignition related.

Here is what I have noticed.
This only happens at night (cool temps) after I have been driving at freeway speeds (65-75 mph) for about an hour.

At first it will seem like I have a slight loss of pwer and have to press down further on the gas pedal.
Then, the engine will bog like its fuel or ignition has been cut. Floring the gas pedal will, after a 1-2 second delay, cause the engine to recover.

This seems to particularly happen after backing off on the gas. (e.g. passing someone and then slowing down, or going down a hill.)

Normal around town driving, this never happens.

If I pull over when it is acking up and try driving around town, it will usually not be able to idle, but will stall.
Turning off the ignition and waiting 30 seconds to reset the ECU does not seem to have any effect.

One last bit of info is that my temp gauge seems to have been giving me false readings it always stays in the cold zone or right above - (when the radiator fan is kicking on it is still below the LED)

Also, I have added a capisitor to the AFM as outlined in the archives.

Any thoughts on how to narrow the possibilites?
I find I am not taking any trips because of the worry over the hassle of breaking down.

thanks,

Todd