I'm running the Sniper 19-365 in-tank pump on a carburetor setup. It says it's a returnless pump with internal regulator set at 6 psi. On my fuel pressure gauge it only reads 4.5 psi. Engine runs pretty good, but I have a horrible idle once I go drive it and get it hot. The pressure gauge is not steady at operating temp. Could this be it needs a return? Also, I have the pump ran through a toggle switch, could that be dropping current to pump? Or maybe when at operating temp the electric fans are on, could that be reducing power to the pump?