:shakehead 1998 Blazer after changing to the new spider assembly(the new one gm came out with) I have a tad of a high rpm when Im drive it does not reduce the speed on its own rpm @ 1000 /1500 A/C on it will go down somewhat I all ready know its not TPI SENSOR OR IDLE SPEED SENSOR SWAPED THOSE OUT?

Sounds Like a vacuum leak to me. But its usually wise to replace the old gaskets anytime you pull them.