Air/Fuel Meter not reading properly

[Poman]

Help! My car has been running like crap for the past month, especially the idle is out of place all the time and the car feels like it's about to stall. I have the timing belt, O2 sensors upstream x2, MAF sensor replaced and it still runs like crap. I do notice my air/fuel meter is not running correctly like before. Before when the car starts in the morning, the meter will show the light slowly move from lean to rich and then bounce back and forth continously. Now when I start the car cold, nothing happens, the meter will bounce back and forth when the car is in drive and I step on the gas. What's wrong!!?? Thank for your comments.