I'm still struckling with low MPG's (low teens) from my new to me 2005 HD Auto. A new intake, Donaldson muffler and Smarty JR have helped but only 1-2 more miles per gallon (at least I have more power!) I was reading some threads on IAT sensors becoming fouled on earlier models and was wondering if it's possible that the K&N oiled filter the PO had on the truck might have fouled my IAT sensor? Do these sensors require cleaning or replacing on 2003-7 5.9's? What about ones just downstream of those highly regarded K&N beauties?
Thanks

 

You can try cleaning the MAP/AIT sensor with a MAP Sensor cleaner from any autoparts store. You may want to change from a K&N since I've read several threads here having high levels of silicon (sand/dust particals) when used with that filter.

To help with mileage air the tires up to max psi when cold & change driving habits to keep the the RPMs under 2000.

 

I'm in full agreement on the K&N and ditched it right away. RPM's are down, way down. It's amazing how far these things will roll.