missfire on Cyl 2. At a loss, please help!

[KS300]

I have done A LOT of troubleshooting so bare with me... About a month ago picked up a 84 300d turbodiesel with 173k miles. started and ran perfectly but previous maintenance was unknown so I adjusted the valves (all exhaust too tight, most intake ok or slightly loose) fixed all vacuum leaks and replaced all fuel hoses along with the primer pump. Test start the car ran fine but the next day after a long drive it began idling badly and smoking greyish smoke at idle (especially while cold). i figured an injector was bad so decided to replace all of them with new bosch injectors, but this did not solve the problem. I narrowed it down to the number two cylinder by cracking injector lines one by one. it ran worse with each except cyl 2 which cracking the line did nothing. I tried swapping injectors around just in case and issue always stays with #2 cylinder. At this point i figure I must have messed something up with the valve job so I redo it entirely taking extra care at which were exhaust/intake and getting them PERFECT (slight drag with cam lobes in 1 o'clock position/90 degrees to platform lobe makes contact with). all were fine. I bought a compression tester and cylinders 1,3,4,and 5 were right around 400-425. cylinder #2 was 290. I poured a few ounces of oil into the cylinder let it soak for a bit and repeated the test with compression only going up slightly to 300-305psi. so I checked and redid cylinder 2's valves AGAIN with everything looking fine and checking out. Additionally I have inspected the pre-chamber and it does not look particularly dirty with the ball and glowplug in there correct places. No oil in coolant no overheating issues smoke does not look or smell like coolant. I am about to pull the head and inspect the valves or just give up. Any ideas of what could be causing this? Prior to the compression test I was dead set it was a fueling issue but now I'm thinking there is not enough compression to ignite the fuel at idle on cyl 2.

TLDR bullet version:
-om617 turbo motor with essentially no blowby doing oil cap test
-has great power and runs PERFECTLY off of idle.
-cylinder 2 is not igniting fuel properly at idle causing misfire and puff of smoke
-brand new injectors and no air leaks in fuel
-Cyl 2 has 290PSI of compression (100PSI less than neighboring cylinders)
-car ran fine before valve adjustment after adjusting its almost like the valve no longer seats correctly.
-I have adjusted the valves 3 or 4 times at this point, Cyl 2 is Intake then exhaust and setting gap at .10mm and .35mm respectively.



Thank you for reading all this, any help or suggestions are greatly appreciated. Hoping someone out there has an idea i do not!