Minor exhaust leak hinder MPG's?

[PitbullRescuer]

I have a minor exhaust leak, the muffler has a little rust so I'm sure it's an easy fix. Just curious if anyone knows for sure if this would be hurting my MPG's?

In the last 4 months I replaced the fuel filter, air filter, PCV valve, plugs, wires, O2 sensor, tightened the throttle, kick down and cruise control cables and cleaned both the MAF and TB.

Truck runs fine, I'm 34 years old so I don't really drive line a knucklehead, I have stock size tires. But, I barely average 15 MPG's. Mostly city driving, probably 75% city.

The only thing I can think of at this point is maybe the exhaust leak is somehow effecting it. Not sure how but I don't know what else to replace.

 

[4-Ripcord]

Besides the pressure in your tires, I have no idea. You have all the bases covered. No idea why your mileage is where its at.

Good time for a TRD exhaust, I'd say!

 

[Maritimer]

My exhaust had two leaks up front, and on both sides and the top of the muffler. It got about 10mpg the last week of dying. I'm sure small leaks will mess things up, especially if they are in front of the O2 sensors.

 

[PitbullRescuer]

That's the thing, I can't find any in front of the O2 sensor. Doesn't mean they're not there but the only leaks I see are on the muffler.

Did you fix your exhaust? And did your MPG's improve? I'm tempted to pull it all off and gut the cat while it's apart. It my understanding that a clogged cat will kill your MPG's. (although I have no idea how to tell if it's clogged.)

 

[Maritimer]

I'm still in the process of getting an accurate mpg improvement. I idled it for a while during the first tank, cause I was doing a bit of cleaning in the freezing cold, and the second fill up I was driving aggressively in town, and the tank didn't actually fill as the pump stopped under full. So, those numbers are shot.

From immediate appearances, though, it looks like it is doing much, much better.