why does my car hesitate to pick up speed

I have a 2001 mercury sable that stalls every time I press on the gas pedal.

I'm still losing power on a straight road. Close to $3,000 in repairs since last month. My Millenia has been in the shop at least 6 times this past month. Each time its a different code , a new repair and the same problem still exits. Getting really afraid to drive this car. Last repair was a new timing belt! Technicians can't seem to figure it out! Please help!!!!

Sure sounds like a vacuum problem.

my car when i pick up speed dont pick up speed