Boost fuel economy

[muncie21]

Best (and cheapest) thing you can do is change your driving habits.

My 2009 6.2 Denali XL has reliably provided combined city/hwy MPG of ~14-14.5 for the past 3 years. The 5.3 Suburban before it got 14.5-14.8 routinely on the same route to work.

 

[George Owens]

Changing the 02 sensor if you have over 100,000 miles can improve the fuel economy. The 02 sensors wear just like a spark plug does.

I'm assuming the upstream o2?

 

[George Owens]

Also where's the fuel filter

 

[calif phil]

I'm assuming the upstream o2?

Yes. Just the upstream sensors. I would also buy quality sensors like AC Delco or Bosch.