Hello fellow Mercedes enthusiasts! I am new to the forum and I don't really know what I am doing so call me out if I am doing something wrong, But basically I am hoping for some advice from some people with experience as that's what forums are for right?

So my W123 wagon shakes reeeealy bad at idle, like I get a real massage at red lights, but it only shakes below 1100RPM and some RPMs below 1100 it doesn't shake at all. The amount of shaking changes based on if I've just come off the highway, weather or not the engine is hot or cold, and the "frequency" of the shake changes also with these factors.

It has been sorta shaking ever since I bought the car, but I have barely any blow by and the engine starts up instantly as well as shuts off with authority, so I never thought to do a compression test (even though that's the first thing you should really be doing on a car you just bought with 550000k). I did a diesel purge (nothing happened) and even found some brand new injectors for it. The injectors actually made the shaking significantly worse which was a little annoying.

So anyways before I spent anymore money on the injection system I figured I should probably do a compression test to find out if I have a low cylinder, so I did a valve adjustment and got some "results"

Cylinder 1 was at 380 and then, well, I broke my compression tester. The rest of the cylinders all read exactly the same 320 but the gauge quickly leaked all its air out, in my opinion this would mean I can't really trust my compression tester. I needed to get my car back together so those are the results I have.

So basically at this point I am wondering where to go from here, this was a compression test on a fairly cold engine (<10C) and all I know really is that every cylinder has more than 320PSI. When I first got the car and dismantled the turbo, clearly a bolt or a nut had gone through it, so it wouldn't surprise me if one cylinder is down, but it just seems strange that one cylinder was that much higher than the rest, and I figure if a nut went through a cylinder causing the engine to shake so terribly badly wouldn't it be below 320PSI, and if it was a bad cylinder, why would the shaking and type of shaking change based on all these strange factors (temperature and etc)

Anyways I am just curious what everyone's opinions are on the matter, is my compression at the (best case) 380 or worst case (320) to low for me to bother doing anything, should I keep working on the fuel injection system, or should I just run this thing with the shake and try my best to ignore it.

Thanks!