2000 Chevy Impala Car wont stay running

I recently got in my car and tried to start it, it turns over and only stays running if i hold the acceleration pedal almost to the floor. If I let it go it boggs down and dies. I took it to midas and they told me my intake manifold is cracked, my evap line was bad, and that I need fuel injector o rings, all of which they wont guarantee will fix the problem. I took the upper intake apart and bought a reseal kit for it to make sure sure there is not an air leak, to my eye they intake was not cracked. I also was told to replace the idle air control sensor which did not fix the problem. I replaced the fuel filter, which hasnt been replaced for quite a while. There is black smoke coming out of my exhaust and white smoke coming out by the valve covers. The engine shakes vigorously when I try to maintain idling. Ive been told to replace the throttle body sensor, cam sensor and crank sensor. Does this sound accurate???? I really would appreciate someones help in this matter.