Camaro37

My gas mileage has dropped to about 9 mpg and I'm sure I have a couple of leaks before the 02s. Will these leaks drop my mileage that low or do I have other problems as well?

I'm dreading pulling the headers off just to do gaskets and was hoping maybe it was my 02s or something else ruining my mileage.

S.J.S.

Depends on how bad the leak is and what type of driving your doing. If its a bad leak and your doing a lot of city driving, I would say yeah because you will lose a lot of bottom end with a large exhaust leak which will cause you to use more pedal getting going. But looking at your post, I dunno how much MPG you were getting in the first place. I don't think it would drop no 7 mpg though.

Z95m6

Yes a leak will kill your mileage. Mine got down to about 90 miles to the tank when i developed a leak on my headers.

Red_94Formula

yes because air is sucked in through the leak causing the o2 sensor to think it is lean. then the pcm will add more fuel then needed. thus killing mpg and performance.