QUOTE(Pard o @ Aug 8 2007, 05:05 PM) [snapback]7333[/snapback]
Fairly High: 2100 + ft. Is yours an auto? I think I have some kind of exhaust blockage.
Well, 2100ft is fairly high. Most engines have stated power ratings based on sea level. So when you gain altitude, you lose power, especially with non-turbo diesels as there is no High Altitude Compensation system. You have less oxygen available therefore the diesel doesn't burn completely and you lose power. You will find that your van blows more black smoke (soot = unburnt fuel) than it would at sea level.
This is where turbos are better as they help to push more air into the chambers and thereby increase efficiency.
Yes, my van is an auto - but we are at sea level here so it runs sweetly.
Last year I took it down to the South Island and spent 10 weeks working at the top of a mountain - high altitude. On the climb up the mountain, the higher I got the less power I had and the more black soot I was blowing.
You could try having a more free flowing exhaust system fitted. Being diesel you don't need restrictive mufflers like you do with petrol engines. A nice 3" system from front to back will help it to breathe easier, and make sure you change your air filter regularly. It's all about allowing the engine to breathe properly.