1999 Pontiac Grand Prix engine runs terrible on and off

I am having problems sometimes when I first start the car it idles real rough, then when I give it gas it starts missing real bad and sometimes dies all of a sudden like when I take off from a start. Other times it runs smooth then all of a sudden it starts running bad just out of no where. And if I give it a lot of gas it will snap out of it. It seems to be getting worse its been going on for a few months or so but like I said it is doing it about 50% of the time now, I give it gas and it starts spitting and sputtering until I give it full throttle then it snaps out of it.
another problem is when I'm going over 60 and I need to use the brakes the steering shakes all over the place I replaced the outer tie rod ends not too long ago I also hear a loud noise sometimes when going around a tight corner. I did notice the rubber grommet on my right lower control arm is like cockeyed and looks wore. Maybe this is the problem I don't know but any suggestions would be greatly appreciated. Thanks so much for you time
kevin