Engine Surges, idles high and starts to jerk hard and a whining noise from inside the motor

I have posted information about this problem before and although I did receive help unfortunately it did not fix my problem.

I have a 2000 Chevrolet Impala with a 3.8V6. When pulling away from a stop or just simply when I start to accelerate my car will suddenly surge repeatedly. This does not go away until I reach roughly 65mph. The problem is I have replaced many many things lately and nothing has fixed the problem. Initially my car was throwing code P0171b which indicated a lean bank. The problem is I have replaced all my vacuum lines, both 02 sensors, the catalytic converter, the MAF, the MAP, the TPS, the IAC and most recently just replaced my valve cover and intake manifold gaskets. The problem is still there. I have had all these repairs done within the last 5000 miles of my cars life. The problem now is my Air Bag light stays on, along with low coolant which I know is not an issue. Along with this the car still surges. I dont know what to do now as I have no clue where to go to troubleshoot it as the codes are gone besides the air bag, I can find no evidence of leaks of any kind either. I have taken this car to multiple mechanics who have no idea one of which whom is a personal friend is at a loss at this point. Can someone give me any ideas?