Poor running engine right after cold start

[civhatch90]

Hi everyone!

My father has a 1997 F250 diesel with auto tranny, truck is 100% stock.

The truck has absolutely no problems starting. After a block or two of driving, it starts missing and looses all power barely stays running. Smokes a lot. If I let it sit for about 10 mins, it slowly starts running better and better. When its fully warmed up it runs normal.

My father has taken it to two different mechanics a total of FOUR times and has already paid for repairs of X, Y, Z which where supposed to be the cause of the issue. Nothing was fixed and the truck still has the same problem.

Any thoughts? Thanks

I should add the truck throws no codes.

[melmount]

What was done by these mechanics? Any codes?