my grandfather has a buick .... roadmaster i think. well anyways it has an lt1 engine in it. when the car gets hot it just randomly dies until it cools down again. Is this the optispark ?

 

could be the idle air controller passage way is getting gunked up, when it heats up it's binding and can't keep the correct amount of air going through to keep the engine at idle. just throwing out a maybe. good luck.

 

anyone else have any input ?