86 Vanagon loss of power

Our Volkswagon van occassionally loses power and dies. Generally this only happens after driving for more than 2 hours. It seems to be more likely to happen on twisty, hilly roads where you are speeding up and slowing down a lot, although it’s also happened on an open stretch of highway. We’ve also noticed it occurs more often when on a long trip which involves a gradual drop in elevation. Only once do we remember it happening while gaining elevation, and that was 5 years ago. Not the easiest thing to recreate at the mechanics shop. But we frequently drive over an hour into town and have only once had a problem on that drive.

In the past, we have had similar problems. Going down the road the van would leapfrog and hiccup and finally die. The first time it happened, there were two occurances on a 900 mile stretch, but with the second occurance it died completely and wouldn’t restart. A good group of folks down at Austin VW spliced a fuel injection harness for me that had fried from touching the catalytic converter.

5 years after that, it began to recur. This time it happened occassionally for a year and a half, before once again it finally died completely and wouldn’t restart. This time the alternator (or was it the starter?) was replaced. For a few years it was fine. Then it started to happen again, but not with so much bucking and sputtering as before. It just gives a couple hiccups and slowly loses power and dies. After resting 10 minutes or so it starts right up again. It has continued to happen occassionally for the past 5 years. We have a toddler now and a baby on the way, so we’ll probably be stopping enough on road trips that maybe it won’t get a chance to happen. But the one time I mentioned that it happened just driving into town, my wife was stuck in the dark by a curve on a snowy road with our son and the dog in the car. And 6 months pregnant.

Is it easy to check the fuel injection harness? Or are there any other suggestions?