Sick Buick engive miss

[Super Racer]

1990 Buick 3800 engine 108,000 miles. No codes in computer. Cleaned injectors, new coil pack, Spark plugs.
The car has a miss until it gets to hot operating temperature. Then it's like a switch is turned and it runs like a watch. Goes down the road like gang busters and idles fine.
Shut the car off for a couple minutes then the missing process starts all over again. The car gets to operating temperature and it's OK again, like flipping a switch. Low speed high speed it acts the same. Once it's hot it goes fine,idles fine.
It has been like this about a month. I have driven the car on 2 long trips involving 2,000 miles and it acts as I said. It don't seem to be a real problem more of an annoyance also embarassing, when next to someone at a light and it is doing it's missing routine.
As long as it's semi not warmed up it runs like a sick pig.