Cylindar 1 Misfires detected...? I get weird popping noises right after doing an up pipe, only under acceleration in gear. If I rev the engine at a stop it sounds fine. Also it seems to be "growly" when accelerating, this could be normal with the pre-cat gone? Could it be a loose manifold nut making the knock sensor go off? I don't think I have an up pipe leak because I don't have the screeching sound I've heard described with uppipe leaks. Whats going on ?!?!?