Just got back from a trip to indiana and i checked my mileage, runnin 70 mph and had my ez on and my tst on level 1. i only got 16.5 mpg. doesnt this seem low?? wat are you guys makin and could my vp be goin out?? i have a rough idle for a minute or 2, after droppin to idle after driving it. thanks.

 

whens the last time you changed your fuel filter?

 

With whats in my sig, TST off, Smarty on 3, 21.5 mpg at 75-80 mph. My truck is only 2wd though. Also around 18 in the city.

 

had my truck a year and havent done it. would that cause bad idle??

 

yes, it could cause a rough idle if clogged enough. if you think about it, a clogged filter is cutting off fuel delivery to the motor. i dont have an upgraded fuel system yet, so i dont know how often you are supposed to change those compared to stock. anyone know? i would like to know as well. I usually change my stock every other oil change

 

yea i guess your right. il change that and see if it makes a difference.

 

alright let us know how that turns out

 

What's your fuel pressure? As long as it hasn't dropped any from where it was at the last filter change, it's still good to go.
Mileage sounds a tad low, but it can be any number of things: air filter, fuel filter, IAT or MAP sensors, worn injectors, etc...
How long have you had the truck, and what kind of mileage are you seeing in town?
On my '01 in my sig, I get 15.5 in town and 17.5 on the highway, and this is with ladder racks and ladders on them, so you should definitely be getting a little better I would think.

 

I change mine every 8-10 k regardless of fuel press. I could pob do it a little sooner I think.

It could be winter fuel as well. My milage always dops by like 2 mpg through the winter.

 

Adjust the valves first. Then if the bad idle is there, get the injectors pop tested and cleaned.

 

ok so.... change my fuel filter, and maybe clean my air filter, adjust my valves and check my injectors. i have had the truck a little over a year. i seen around 15 mpg in town. also this truck has 275k on it. also my fuel press. is usually right at 20. now on start up its around 18 and sometimes it goes back to 20 as i drive. maybe this is from cold weather too. have only noticed fuel press. dropping since cold weather.