Asking help Please

Hey, somethings wrong with my 88 944S. when i press the gas pedal all the way to the floor it doesn''t want to go, it actually stops. and sometime''s when i go on the freeway the car hesitates. i recently put in a 3.0 fuel regulater from lindsey and put new gaskets for the intake manifold. what do you think is wrong? please help. thanks

my car hesitates when im on 5th gear, trying to get past 60 mph. and when i down shift, it still hesitates.