HELP!!..........MORNING MISS.......Driving me nuts!!

99' Blazer 4X4 full size 4.3
Has anyone figured out the problem that causes the MORMING MISS?
I've had it in the shop for a total tune up, fuel pump pressure test, changed the distributor out and it's still there. Just in the morning till the engine warms a little, than it will run like new for the rest of the day; no matter how long it sits you can't get it to miss??? NO code.

PS. The miss only happens when I take off at normal speeds. If I take off like a dragster, with the peddle to the metal, it does not miss, Go figure!!
Morning miss started @ about 125000 miles.