2000 Buick Park Avenue 2000 Buick Park Avenue ultra stutter

Ok last week my car started stuttering while accelerating. Idle the cars purrs like a kitten no stutter if u mash the pedal it will speed up but it stutters onced leveled off its fine but if u try to accelerate like from 45 to 55 it stutters like its missing now I checked and cleaned maf also I checked coil pack and the 2 coil pack was a little rusty so I just replaced the car was tuned up maby 3 months ago wires plugs cleaned injecters not sure whats wrong someone please help also I forgot to add it dosent make the service engine soon light come on it did once and it flashed on and off then went off and problem is still there like I sadi crusing like 35-45 even to 75 steady is fine but when you accelerate it studders