About to give up.

I have a 2004 autotragic Rx-8 for the past month I have been having problems with it but for now I just need help. The car now sounds like it is misfiring it heaves when I barely rev it then take my foot off it will drop to 100 rpm stutter then back up to 1000 and bounce from 750-1000, when driving whenever I stop the car it dies and has a really hard time starting back up also I have NO codes and it's really confusing. I have already (due to prior problems) gutted catty, new ssv and gasket, new thermostat and gasket, new waterpump and gasket, new battery (above good), new plugs wires and coils (got new coils today thinking that was the problem no help), cleaned maf and the connection, cleaned grounds, cleaned all connections, tripple checked all of my vacuum lines and replaced both of my belts I have been sharing videos via facebook to the purelyrx8 page, my name is chris cambrice if you think you know the problem try to reach me there as I am not on this forum often but I will be checking daily now and will appreciate and help that I could possibly get. If I left any information out please let me know.