How can I increase the fuel mileage on an 06 suburban with 5.3 liter engine?will a cold air kit do anuthing?and what other things can I do? Thanks in advance.

 

I hear you on that issue too. Am also wondering if headers will help as well too with the CAI. So long as you don't use the extra power, I hear it will help. And would a rear roof spoiler help as well too? Cost hard to justify savings.
I do have an excell turbo charger lying around that use to be on a 1974 Pontiac 350c in. but its rated for 330 to 360c in engines (the 5.3 is only 325c in)

I did get 18mpg with a snow plow attached going 45mph @10^F (too dark to see going faster with the snowplow on) and 16.8mpg @ 55mph on the freeway on a 2005-Suburban 5.3L w/4x4 turned off in cold weather as had to drive it home 200miles.
Just bought the 05 few days ago w/218k on it...

 

do proper maintenance.
the short answer is no. if the manufacturers can't do it....aftermarket can't either. save all the money spent on car jewellery, throttle body spacers, gas tuners, cai etc and put it towards fuel.

 

i think it cas boost it a little but that can also be offset by you using more throttle to heard the roar of the engine. theres some programmers that can also help boost but i cant suggest one, tire pressure and proper size along with how much you use your right foot

 

Using pure gas will improve your gas mileage.

 

Around here non-ethanol fuel costs $0.40 more than 87 octane E10.