Well there is a small leak coming out of the O2 senso bung and I lost a stud on the downpipe flange thats 2 or 3 inches from the O2 sensor. So my best guess is that the O2 sensor is getting some wild signals.240dreams wrote:How does an exhaust leak effect MPG? Thats odd. Are the leaks close to the turbo or something? Interesting. Well I get about 19-20 MPG stock boost mostly city.