97, 2.4 malibu engine pulsing

I have recently been pulling the last of my hair out over this Quad Four. The problem a pulsing idle when the engine is cold or hot. Originally the check engine light was not on, however, it still showed a code for multi-cylinder misfire. I changed the boots and the plugs and erased the code. The problem continued. I also found an intake leak, which I corrected. Guess what. The check engine light now comes on. I also cleaned the throttle body and the idle control solenoid. Didn't help. The computer showed the same code again. I took it to the dealer. They told me that both coil packs, spark plugs, control module and EGR valve had to be replaced. Did that, still have the problem. Finally a code popped up for the MAP sensor. Changed it, still have the same problem. I cleared all the codes again after changing everything. No codes have reapeared, but the problem still persist. I have also gone over the vaccum lines, they all appear to be fine. Someone please help, my hair is gone and my sanity is not far behind. I would greatly appreciate whatever help I received.

Did you ever find out what was wrong with your car? I'm having similar problems with mine........but I haven't dumped a ton of money into mine......yet! Please let me know if you found anything that might help me.......Thanks!!