i think it gets worse at lower fuel but it seems to do it all the time. anytime i floor it down low it bogs or surges or some sh*T. i watched my air/fuel when i did it and even though it isnt a wideband, when i gassed it the gauge went to full rich but bounced back real quick before going back to rich like normal. im wondering with that bounce back reading, if it is just another indication of the fuel. and im pretty sure its not the secondaries because i know the normal feeling when they open and that hasnt changed.
