I have a 1997 F-150 4.2 v6 and my muffler was rusty and had a small hole so for ChristmasiI got a thrush welded muffler and it sounds great but its decreasing my mpg and I don't know what to do. Someone had said I need to get the computer reconfigured but I don't know how you do that or where I need to take it. What should I do?

 

MPG always goes down for a while after getting a new setup. You're in it more to hear it, so the mpg's drop. They'll get back to normal shortly.

 

There is nothing to change in your PCM for a new muffler. The engine does not know and cannot tell a difference with your config.

Whoever told you that does not know these trucks.

 

I was told anything you do aftermarket performance wise you are to unhook the battery for a few mins to reset the computer not sure if that is true or not but I still do it to be on the safe side

 

I put two thrush turbos, and there was a noticeable drop in mpg, maybe it's just Thrush itself?

 

Why did you use two?

 

True duals man