I just purchased a 1987 Mercedes 300D, the car has 136,000 miles and has good service history. As it’s my first diesel the acceleration when tested seemed normal for a diesel, (slow) until I test-drove my neighbor’s 1981 300D, this was a rocket compared to mine. I found that mine had the oxidizer trap which the MB dealer removed with the recall retrofit. This made a significant difference but still seemed slow. I noticed that the intake manifold had build up of oil; this was cleaned at a machine shop and made a difference but still slow climbing hills. The car was always driven at sea level until now I live on a hill at 2400 feet ASL, I should mention that the valley is at 1100 feet ASL and its fairly steep climb. The car starts first crank every time, after the initial bit of smoke and roughness, the exhaust comes out very clear and idles smoothly. My question is, is there an adjustment and or a mechanism that compensates for the altitude. On flat road at 60MPH the car cruises at 2200 RPM. There is a noticeable difference in acceleration above 3000RPM, but getting there is slow. Climbing hills is very slow, any suggestions.