I just got an 06 with 40,000 miles on it it has an exhaust brake and 4.10s and all Im getting is 12 mpg empty 10 with a empty gooseneck trailer is there any chance the cats plugged or what can I do besides slowing down to get better mileage Im already down to 70 on the interstate it doesnt seem to have a lot of power either. my 01 with 275 injectors will out pull it. any help would be appreciated.

 

I have read several post with members complaining about poor milage with the 4.10 rearend. So you are not alone. On my 3.73 I seem to get the best milage between 1800 and 2000 rpm.

When you change tires you might think about a taller tire to get a better ratio.

 

An 01 with just 275 injectors should not outpull an 06, not even close.

I would check your intercooler boots for a tare or loose clamp. Check intercooler for a hole from flying debrie. Does the truck smoke when taking off or towing? Any way you could check your boost numbers?

It's possible the cats plugged but highly unlikely, I've never read of one being plugged yet.

 

I will figure a way to jury rig a boost gauge and see what it says thanks for for the help.