Definitely , you can adjust your car's RPM. But first of all make sure, there is not much gap in your throttle(butterfly) and not any vacuum leakage. So 1st step is to check all this , and secondly , lose the choke sensor (mostly attached to throttle body/intake manifold) and then lightly move it to right or left, you will see your RPM going up and down accordingly. Adjust and tight it where you want your RPM to be.