Hi. I recently replaced my ECU (it seems to have fixed the issues I was having - gas/temp gauge, key stuck in ignition, TC & Security light on) and now that I have the new one in, my car is running super rough. The diagnostics are showing a misfire at cylinder #5. I replaced the coil but it did nothing. It was recommended that I try replacing the spark plug, which I will do tomorrow. So my question is why would my car be running fine with the bad ECU and now that I have the new one I have a misfire? I even put the old one back on and the car runs fine. I'm hoping someone can help me make some sense of this. Thanks in advance.