I have an exhaust leak near the headers somewhere. I can hear it but i havent really had time to look for it since i havent been driving the car too often. it runs weaker than it used to but idk if that is just from the latest tune up. Could the lower amount of backpressure be what is making the car so hard to keep running???? I mean i've had to pump it quite a bit to keep it running...then it is fine. Well, how important is it to fix??? (im a cheapskate and am selling the car)