11.45 mpg in town 16.847 mpg hwy..what's wrong!!
 

I've owned my 03 for a short period of time, when I first got it I was seeing mid 20s on the highway and 17 around town my milage has dropped horribly I've got an air dog pump just put new filters on 500 miles ago air filter was blown out a few weeks ago, no codes no leaks I can seem to find it gets the same milage with the tuner on or off, what the heck is going on!?!?#?#?#?#

Please tell us what tuner and other mods you have. Did it start doing this after the last PM that was done? Is the truck running rough?
Welcome to DB :tu:

It's got a 3" leveling kit, bully dog rfi, quadzi ll xzillaraider 2 programmer 4" straight pipe to 8 inch stack and yes it was not long after the filter change I noticed it, not sure what to do and thank you for the welcome

Bumped this back up, anybody got any ideas?
Seems either the tuner isn't working or maybe a fueling issue like an injector.

Any smoke on start up in the morning? Any blow by? Could be a dead hole "melted Piston" That's worst case! Need more info to narrow it down!

No smoke and not a bit of blow by, starts normal, no noticeable loss in power. I'm stumpped

Anyone have any ideas?

The air dog may be putting more fuel in and your still getting full combustion possibly? The pump is the only thing i can think of.

What kind of boost are you seeing?

my boost still seems the same, at wide open i see 40psi and my usual commute it is at 0 just farting along at 30 at 45 it varies but usually under 15psi

Check your oil level. If too high, you could have a failing Injector(s), and your oil will smell of diesel. If not, give it a good healthy dose of injector cleaner, and run the hell out of it......see what that does for you.

Thanks, I hope something works

Easy test to check if there is diesel in your oil is just pull your dipstick out and let the oil drip onto a piece of paper and the diesel will separate from the oil and leave a much lighter color ring around the oil.

Has anyone had any sensor go bad or act up and cause a drop in milage lime this?

a very dirty IAT sensor would cause your fuel mileage to plummet. On your 03, I believe its located just aft of the air filter box. In fact it should be attached to the lid of the stock air filter box. Its held in place by 2 small torx screws, and has a 2-prong electrical connector. Try cleaning it, carefully with a q-tip and rubbing alcohol. If your using an oil type air filter, the IAT will become covered in oil residue and fine dust, hampering its effectiveness. Give that a try. Also, check your tire pressure. Have you given any thought to wearing/ worn wheel bearings, extremely dirty brake calipers preventing your brake pad(s) from receding and causing it/ them to drag abit on the rotor(s)? How about a slipping trans or converter? Just thinking outside of the box......:humm:

I believe I do have an excessive amount of brake dust showing on my rims but the truck coasts fine and just once in a blue moon if I let off the throttle and let go of the wheel it will pull just ever so slightly to the right, the pads are new from when I bought the truck, I chalked it up as shitty pads the dealer put on, since they've squeaked since I got the truck

You may have a sticking caliper, or your alignment is off a bit. I have high quality pads on my rig, and they squeak so bad its embarrassing, but they work well. Other than what I posted earlier, im pretty much stumped.

Does it make any difference with the tuner off or on? I wonder if the tuner could be not working. :humm:

Clean your sensor By your air filter. Check your Rail pressure sensor on the rail. No codes no smoke.... has to be your tuner or your right foot!

Did you ever get that issue figured out???