94rx7speedracer

i have an issue with my ignition...i think, but i just wanna make sure by asking. My car runs fine until i get the secondaries opened up, thats when my car will bog down and backfire. i took the plug wires of the front side plugs one at a time and then the back side and the front side seems like its firing slower than the back. the car smokes sometimes also and it didnt do that before this problem. Can someone help me diagnose this so i can fix it? Much appreciated.