cold start

I would start by dissassembling the battery connections and cleaning and reconnecting them. When you cold start the car actually need more juice to crank it. If the connections are sketchy, you might have the above issue. could also be a bad connection at the starter end. Could also be the battery or starter.

Marty

PS you aren't an orthopedic surgeon are you?

If the battery terminal clean up and tightening doesn't do it and you're not using Mobil1 then you should try it because it's viscosity remains low at low temps.

Forget an air leak into the fuel system for that would occur all the time - or at least every overnight shut down. Slow cranking by the starter is electrically, not fuel related.

Don't take the battery for granted - it may well be the problem. Otherwise the starter becomes the suspect.

Problem solved. The engine was cranking on three cylinders, 3 of the glow plugs were gone.

Charlie Brown