6.0 getting 9 mpg empty

[Ruger5901]

I've got a buddy in Cali that has a 6.0 and is getting 9 mpg. No mods and on 33s. Where should he start?

 

[Nic]

Batteries checked, FICM voltage checked, exhaust, delete, new oil cooler, coolant filter and VERY light economy tune. Start there.

 

[sootie]

fule filters

 

[Lassie]

front end/ locking hubs

 

[Nic]

fule filters

that too..Use Motorcraft only for sure..And fuel pressure checked. If he doesnt have the blue spring update kit, advise him to do so.

 

[Vinny07psd]

Clean air cleaner

 

[Vinny07psd]

Fuel additives

 

[loboost]

Exhaust & boost leaks

 

[Twan]

Did he just buy it, or did it just start getting bad mileage?
Sounds like he drives like me too!