I have 92 s10 blazer 4.3 TBI it starts fine and idles fine until it is around halfway up to temp. It then begins to miss and sputter very bad, usually stalling. Starts after a minute or so and once up to normal running temp runs fine. Once again it only seems to do this once it has warmed up bit.

 

I would suspect the EGR valve needs cleaning.

 

thanks...is there a thread discussing the best way to do this?

 

About a bazillion . Use the 'search' function for 'clean EGR', 'EGR cleaning', etc.