Have a car that's doing this bad and have seen it on a couple others but it doesn't seem to be "normal".

Basically, the RPMs drop when the car is shifted into gear/drive from park/neutral.

In a severe case, it kills the engine when the car hasn't warmed up enough.

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What is the idle RPM? If it's too low I could see it stalling with the extra load of being in gear.
Is the engine shaking more when in gear as well, if so that's a sign of a bad trans mount.

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The governor in the injection pump should maintain the idle speed regardless of whether the car is in gear or not -- in a perfect world (when the car is new).

I have owned two well-used cars where it would not, and was told it was just a case of the governor showing wear. On my pooched SD it was really bad.

As Biodiesel300td pointed out, however, if your base idle speed is set really low, this can cause problems (particularly shifting into gear when the car is still cold). However, if it does it when you are at operating temp, then there is a problem.

I see you have three diesels, which car are you asking about?

(If it's the SD, how much of a drop are you seeing on the tach, when you put it into gear?)

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

This is only on non-turbos, my 79 300d and a couple other people's cars.

Don't know the idle rpms, no tach in any of those and don't have a means of measuring externally.
I haven't tried adjusting the idle as I still need to pick up a deep-set 14 socket. Just thought there could be some other issue going on as the drop is somewhat significant when shifting into gear.

The governor is on the back of the IP below the shutoff valve? Same thing but different name for the rack damper bolt?
So you're saying the fuel/air mixture could be set wrong?

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