The plate that connects the exhaust

[mywhip]

The plate that connects the exhaust together (After the cat, before the muffler) broke on the truck a couple weeks ago. I thought it was just some holes in the exhaust, so i took it to the shop to have it checked out..turns out it is the plate. What is it called?

Also, would the breaking of that plate (making my exhaust fall, and thus being loud) ruin my gas mileage? I have noticed that i got 60/100 MPG out of a 1/4 tank of gas, which is killer. I drove all highway to bowling green this weekend (93 miles) and it was just at about a 1/4 tank down..which is kind of odd, as i can tend to get about 120mpg out of a 1/4 tank all highway. I need to do a tune up on the truck, which needs to get done soon, but is this what is hurting my gas mileage?

What metal is the exhaust made out of?

 

[martin]

I think what you're describing is a flange. The cat is made of stainless. the rest might also be stainless but more likely ordinary steel. The exhaust broken at that point will definitely affect you fuel milage.