Advice needed on my smoking, missing 240d

[1981_300sd]

Hello all.

Since it has been cold around the start of winter, my car has been excessively smoky, the worst being when its cold and gets better as it warms up.

As it warms up it also "misses" and lacks power - which is restored once fully warmed up. Once warmed up it runs like a champ and zero misses.

I have already done many searches, and have followed suggestions others have done as follows:

Replaced air filter
Replaced fuel filters
Checked operation of glow plugs via jumper cable method - all glow orange
Checked cables going to glow plugs for voltage with tester light, all plugs show voltage.
Ran 2 bottles of diesel purge through it

The only thing that has helped a little but not fixed the problem is adding power service diesel kleen to the tank.

Anyone have a suggestion on a next step I should take?

Thanks!