Astro hesitates rythmically when warmed up

[shockdoc3]

Need help.!!!
Have had problems with another Astro which drove me crazy trying to diagnose, so this time I'm asking for help.
My 98 Astro runs fine when cold. After 10 min warmup it starts to sputter every three to four seconds.
Almost like for that One second, fuel or spark dies. (at idle only). Step on the gas and it will hesitate, sputter and sometimes appear to be stalling. Once and a while it will stall. However once it gets past go, it will drive fine.
It has 90K on the 6 cyl. Tried playing with the EGR. but I can't start on a wild goose chase again.

Anyone know of this problem???
Would greatly appreciate some input..

[ihatemybike]

Is the check engine light on?

Has the fuel filter ever been changed?

A 1998 with 90K I would think is close to the end of life for the fuel pump. Can you check the fuel pressure?

[Kabey's Van]

May be a vacuum leak. Check your intake manifold and thottle body bolts.