I just recently had the AFM tuned out and lost 1 MPG. I really didn't think I would lose anything. Doesn't matter to me anyway. It is worth the 1 MPG loss not having to listen to my truck sound like Im switching on a jake brake every few seconds with the Dynomax exhaust.

You may or may not experience the same results. Just wanted to give a heads up.

 

And thanks for the good information, there's a lot of guys on here that can use it.

 

It just occurred to me that I installed the Dynomax Ultraflow 3" single cat back just shortly before the AFM was tuned out. I have been running the stock exhaust since the truck was new.

Could it be the exhaust that dropped my MPG? I doubt it but wanted to mention it.

 

Def not because you went to aftermarket cat back if anything you should gain mpg as long as you can keep your foot out of the sound pedal lol, I put a dual corsa sport cat back on and noticed a 2mpg gain on the DIC .........after I grew up!!!!!

 

are you going off the truck DIC. with the afm on mine read 1-2mpg better then calculated. when I turned it off the DIC read with in a 10th or two of calculated.