I know this question has been ask but I haven't been on the forum in a while.In the begining of the summer I was getting 14 mpg and now I'm getting 11 mpg.I've changed my air filter haven't checked plugs yet, it doesn't skip or anything.Can ya'll give me some ideas of what I can do to help my mpg's. Alot of people have told me they have had the same problem ever since gas prices have starting going up.Do ya'll think it has to do with the quality of gas or is it just my truck?

 

Check plenum gasket for leaks, - pooling oil in the intake manifold, pull air hat and look down TB blades with flashlight. Parking on a slight incline helps it pool in the back where its easiest to see if there is a problem.

Check for plugged catalytic converter. Pressure tested at exhaust shop is the best way, but you can also infrared temp gun it. If exhaust pipe is hotter before the cat than after, it's not working right.

Clean your O2 sensors. Pull 'em and spray them with electric parts cleaner.

 

agreed with almost everything aim said... I believe however the temp test is a better indicator of the cat's health... output temp should be 10* or higher than the input temp for normal operation. if the input temp is hotter than the output temp, the cat is plugged. if input = output, not plugged but it's dead.

have someone rev the motor to about 2k rpms and hold it there while you check it

 

Bump for this.

Also,check all the other stuff that could affect it as well,tire pressure,dirty air filter,if it hasn't been tuned in a while it couldn't hurt either.Every little bit helps.

And if that doesn't work try acetone.Just kidding,thats a whole nother discussion.

 

in the days of carburetors
a clogged air filter slightly affected MPG

with EFI, oxygen sensors, and PCM computers
a clogged air filter DOES NOT lower MPG
and a less restrictive air filter DOES NOT improve MPG.

Auto companies engineers have known this for decades.

When was the last time you saw an advertisement from Chrysler
saying the new air inlet design on this year's model improved MPG.
Never.
But the ads list dozens of mods that are claimed to improve MPG,
like those on the new 2009 Ram.

Why wouldn't Dodge say that they had improved MPG the air inlet system on the 5.7 Hemi ?

Why would GM tell you that a tiny change like sealing the headlight holes a little better improves MPG but never mention changing the air inlet system?
http://www.signonsandiego.com/uniont..._lz1d10gm.html

Consumer's Reports magazine recently tested vehicles
with both clogged up and new air filters
and found no MPG difference.

Hot Rod magazine technical advice columnist Marlan Davis recently consulted with a friend of his at EFI University and then publicly admitted that he had been wrong too.... that air filter restriction does not lower MPG in daily driving.

On a wide open throttle dyno test
a less restrictive air filter will show a tiny fuel consumption gain,
but daily driving is at part throttle.

Why remain stupid
when your fathers and grandfathers spent years
trying to make everyone who lived after them smarter?
Will you pass on correct knowledge to your children to help them compete against China and India?

 

when i put my k&n cai on i never felt any power gain or any mpg difference. i feel it was the biggest waste of 300$ so far with my modding of this truck. i already had the k&n drop in,wish i would have stuck with that. the only thing that i have done that actually helped my mpg was when i installed the hypertech max energy.a small performance boost, but it gave me 2-3mpg more consistantly,in town or highway.being that i was only getting 10mpg before,2-3mpg helps.