I have a 1987 300td om603

I recently came into an issue where the car will misfire and smoke white at idle. The smoke smells of unburnt diesel.

The issue started randomly and used to come and go. I removed and cleaned the injectors, and since then it has gotten worse.

It seems to be cylinder 5. With the car running, I go through and crack the lines on the injectors and it seems as if cylinder 5 does not change the way it runs. I have swapped injectors around to see if the problem moves, but it does not seem to move.

I sprayed the chambers with soapy water and have not noticed any leaks. I have not noticed any leaks besides an oil leak on the bottom of the IP. Potentially a small diesel leak where the lift pump meets the IP.

Compression numbers where all near the 380-390 range with one cylinder around 320.

The curious thing is, when I run the car off a can of Diesel Purge it runs like a dream. The smoke stops completely, the engine quiets down, and it stops missing.

Does anyone have ideas on what to check?