Stumbles on acceleration?

My car idles smoothly and there no lights on, But once it gets warm it stumbles on acceleration, but once i get speed up it runs fine again. No check engine light comes on ever.

This is stuff I've replaced so far:
Fuel Pump
Fuel Filter
MAP sensor
EGR Valve
Barametric Pressure Sensor

And it still does it! DO you guys have any ideas?

Throttle position sensor? Check with ohmmeter for drop outs in reading as you sweep the throttle open and closed. Might have a dead spot. Seems like it would do it when cold, too, but maybe running rich cold mixture overcomes the glitch.

Dear KingDiamond.
I had the same trouble with my 1999 Lumina. I brought the car to the dealer and had my EGR valve cleaned. Additionally, the dealer put a can of "Sea Foam" in the gas tank and told me to put a can of this stuff at every oil change. This worked well considering the numerous problems that I have had with this car; some 38 repairs in the first 18 months which includes a new 3.1 engine that Chevy put in under waranty.