My '89 was doing that for a while. Started off slowly enough with a slight hesitation when I accelerated from a stop. Also had bad gas mileage and towards the end it would bog down while driving with black smoke billowing out the exhaust. Turned out to be a vacuum leak at the oil breather tower. Unplugging the O2 sensor got me by so I could drive it without too much of a problem but I did get around to fixing it. I diagnosed mine by wrapping tape around the top as tightly as I could and low and behold everything improved. Hope this helps. 

Kenny

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On Nov 7, 2011, at 5:03 PM, Automatic digest processor <LISTSERV@GERRY.VANAGON.COM> wrote:

> Re: '87 vanagon camper hesitating/bucking and burning gas in Mexico