Dear Van Owners:

I have a 1991 Camper Van and she is running very rough on the highway, losing power, sputtering, blowing black smoke and running way too rich ((I think)).  The van never dies completely.  This problem is intermittent and may only happen one day in three and 40% of the time on those days but when it does, it can get severe and it has been towed on occasion.  Several good mechanics have looked at it and can't find a thing wrong with it.  Now we are starting to play the expensive game of randomly replacing parts.  It only has 4000km's on the new engine and has only done this since it got the new engine.

We have replaced the air flow meter, O2 harness (two years ago), and it continues to do this with these adjustments.  

It is most noticeable up hills and on flats when there is a constant rpm.  It is not nearly as noticeable in the city.  When I aggressively rev the engine up to 5000rpm, it seems to temporarily clear the problem for a few more miles down the road and then it starts again. Also, the problem seems less noticeable when I drive the van at a higher rpm range.  I was sure the new air flow meter would fix it but no such luck.  It did seem better for a while but it sat in a snowbank all winter after the new meter was put in.

Any advice would be great and  I feel fortunate to have access to so many great mechanical minds.

Yukon Girl,

Lyn.