I have B16A engine with lightly modification.My question is with the stock fuel pressure (stock set at 36 Psi) the engine I think running rich.Because I just drove the car for 10-15 miles and the sparkplug ring became black already.Now I install SARD fuel pressure regulator,what about if I reduce the fuel pressure setting (for example to 30 Psi) will this help my car, so not running rich? thanks.