98 grand prix slow acceleration

hi i have a 98 grand prix gt v6 3.8 not supercharged, i just changed the lower intake gaskets on my car the car seems to be running good,i noticed when im at a complete stop, and start going the acceleration, seems to be a little sluggish , doesnt really have a good takoff speed, as it did before the installation, also seems to be a little louder exhaust, and once i speed up on the highway ill have the pedal to the ground and the acceleration slowely goes up deffinetly not like it should, normally you would feel the engine kick in!, just seems to holding back can someone help me please

did u double check all the vacuum lines were/are connected when you reinstalled the upper intake manifold?

yes i did check the lines, 2 lines broke, the larger one that comes from a sensorto yhe throttle body and the other one is a smaller one , im guessing the one that comes from the fuel pressure regulator, but they both join, theres a rubber end where the 2 vacuum lines join and go into the throttle body, i ended up getting 2 vacuum line hoses joined them up to a y connection then one hose going to the throttle body, maybe thats the prob? but the vaccum hoses are the same size but the line from the fuel pressure guage was smaller so is the throttle body getting to much air, im stumped?

hmm, i would not think the size of the vac line would make that much difference in air. im not familiar with the gt vac line routing scheme to be honest.