On my 1984 MB - 300 SD with 215k miles, the car is too slow to take of but on highways it ran fast.When in a up hill the car loose speed even presssing the acelerator to try to get more speed.Tranny is in good shape,engine has valves recently adjusted,on line and main diesel filter are new.Fuel injectors was tested showing good.There are not smoke from burning oil and the mileage per galon are good.Brake pads and parking brake are ok.
I still wondering what can be the reason for this incovinient.
Can you share something about it?
Appreciate.
Thanks.
Nyck:

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Nyck - TX - USA

Clean the plastic line that attaches to the rear of the intake manifold.

It was done and the connections on manifold was dirty and clogged.
I clean it and the full lenght of the hose with carburator cleaner.
Made no difference.
If some another ideia I will be glad.
Thanks for your tip.

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Nyck - TX - USA

Have you checked the compression and injection pump timing? Also, adjusting the ALDA might be helpful.

I did not check compression and pump time seems to be ok.
I never heard about adjust ALDA.
It is that component on top of the injection pump where a vaccum hose is connected. As I know, ALDA is for compensation of the altitude.
Am I right?

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Nyck - TX - USA

That's correct, except that the hose is for pressure, not vacuum.

There is an adjustment screw in the center of the ALDA capsule. If you cannot see a screw there with a locknut, then you likely still have a seal attached. If so, cut the aluminum/plastic seal off and discard.

Loosen the locknut and turn the screw slightly counterclockwise, then test drive the car. Repeat as necessary. Make small adjustments. (Do not force the screw if you reach the limits of its travel.) There is a spring in the ALDA which looses tension with age. Initial acceleration performance will be negatively affected. It is possible that the ALDA adjustment will make a vast improvement in initial acceleration.