hello i know my pump is getting bad because it misfires on accel and high rpms badly and the other day it kept getting so bad for only about 5 minutes that when in N i could stomp the pedal to the floor and the rpms will go to 2000 and drop to 1000 while very badly missing. so i tested the psi on the side of the road and when revved the psi went from 30 to 5 psi. i know i need a pump and i am ordering a 155lph holley for 75 bucks off of 3.8 mustangs next week. anyways my question is will a bad pump make the gas mileage suffer badly. i know it is running to lean but it the ECU trying to even things out and dumping fuel into the engine that is not needed. what is going on.