My 2.0 NA going mad at idle on cold, going to 3000 rpm and drops around 1200 and goes up to 3000 again again and again. First of I’ve make a free fiav mod, that help a little 2000 rpm and still surging, bought new isc from rockauto, ( no difference) rebuild ecu with new caps and clean it (nothing) . The biss screw is bottomed out and there is minimal difference when I mess with it. Could be the gasket inside the fiav? Please take a look, because tbh this car it’s driving me mad.