For a week now my car has been backfiring thru the exhaust and the intake anytime you put it under a load whether its a light load or heavy load once you reach 4000 RPM's and higher. It only seems to do this from 3rd gear on up. Every once in a while it will do it in 2nd but very seldom. The other day when I went to drive it home after work, it started backfiring real bad from 2 nd gear on up no matter what kinda load I put on it. You can rev it up all you want sitting still and it wont do nothing. You actually have to put it under a load. So within the last day I have replace the cap and rotor, fuel filter, control module, plug wires, checked my plug gap, adjustable fuel pressure regulator, I put my factory coil back in. All this and no changes at all. I tried to pull codes and nothing relating to what its doing. I also sprayed carb cleaner all around my manifold and the idle didn't change so I dont think its leaking there. I also disconnected my O2 harness and drove the car and that didn't fix it either. Earlier tonight I cam to almost a complete stop, I was rolling in 2nd gear about 20-25 MPH I had the clutch into the floor I was coming up on a red light and the light turned green and I let the clutch out and went to give it alot of gas and the car did nothing and then within a second it reved and Boom loud backfire and a big cloud of black smoke out the exhaust. The car runs alright if you gradually bring it up to speed but anything more that that and it starts banging out. I need help guys I dont know what else to do. I also performed a cylinder balance test and it was fine.