hi. if you have a tach that you can hook up then you can reset the air\fuel mixture this way. bring eng to op temp . adjust idle to around 600 rpm's. back out both screws from bottom to about 2 1\2 turns.at this point one at a time screw in until motor changes rpm (lower) back out to obtane smooth idle. continue to other side . readjust idle to around 600 rpm adjust again the same way . reset idle screw to factory spec's for car and done good luck