I've a E99 with an exhaust leak. A little bit of background first: I bought an E99 crew cab dually nearly a year ago for a good price, but it came with some issues. You can browse through those in another thread here: Bad IDM fixed, now bad injectors?
Basically I had to drop over $2k to replace all injectors, fuel pump, get a chip, and fix a bunch of other little stuff.
All along, I knew I had an exhaust leak somewhere under the hood. When idling the truck with the hood open I could see a bit of smoke billowing off the top of the motor. Just looking at it I could not and still cannot point out exactly where it is coming from. What I do know is that it's not minor. When idling sitting in the cab, the exhaust smell gets in the cab pretty quickly. My gas mileage has never been above 13mpg even at highway unladen and really watching my right foot.
Now from all the reading I've done, I see that people tend to have the up-pipes fail a lot. I tried (the best I could) to check those out. From the bottom of the truck I can see the driver side up-pipe pretty good and there is next to no soot on it and when looking at it from underneath the truck while running I don't see any smoke around the joint. I'm assuming the other one is similar. The downpipe looks pretty clean as well.
So I'm left with the headers. The driver side of the truck sounds louder than the passenger side, by quite a bit. I'm wondering if I could have a cracked header or a blown gasket. Is this common?
Also, is it common to see a 12-13mpg on this truck with an exhaust leak? From what I hear, I should be seeing more in the 17mpg range on this truck. Lastly, how common is it to have the charge piping couplings fail? when I was doing some other work on the truck, the couplings were covered with a thick layer of oil and grime - I'm assuming that came from inside...
Thanks for any help guys.