compression test 1987 300sdl

[sgt1959]

I have a 87 sdl with over 250000 miles on her. The problem is when I start the engine cold it rocks and rolls and then smooths out once it warms up. Also blows grey smoke til it warms up. I did a compression test and the reading were as follows 1,3,5 and 6 were showing 300 psi and number 2 was showing 400 psi this was with engine warm and all injectors out. my question is where do I go from here ?