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Hi all, I have a 2004 Titan, w big tow, and off road packages. I had been getting 14 - 15 mph until about 3 mths ago, then it started to drop to around 11 on the highway, with the recent low of 8.6! It's been to the dealer twice, first time they said the air flow sensor needed an "update" which they did. No change, second time they see nothing wrong on teh computer. I have changed teh air filter (k/N), air pressure in the tire @ 40 lbs, and have changed the oil. The dealer doesn't know what to do, and neither do I. It's getting to the point where I might have to get rid of it.

Has anyone run into this, and more important, any solutions? I'll try anything, I like the truck, and don't want to get rid of it. Thanks!
 

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have you changed gas stations lately? I know that mine is very picky about what types of gas I put in. Or maybe your station switched to more ethanol. 11 on the highway is really not normal unless its really cold and you have one heck of a headwind while traveling at 90+ miles per hour in 4wd with 35" mud tires :crying:

good luck
 

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Maybe I'm wrong but.....When you switch to the K&N filter, the filter channels more O2 to the engine. Subsequently the oxygen sensor senses the extra O2 and compensates by increasing the amount of fuel to compensate. therefore dropping the mpg but increasing the horsepower.

I was going to do the same thing for the increased power but a tech friend explained it to me and I decided that my power is fine...I need the mpg right now....try switching the filter back and do another mileage check....good luck
 

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Skyboi said:
Maybe I'm wrong but.....When you switch to the K&N filter, the filter channels more O2 to the engine. Subsequently the oxygen sensor senses the extra O2 and compensates my increasing the amount of fuel to compensate. therefore dropping the mpg but increasing the horsepower.

I was going to do the same thing for the increased power but a tech friend explained it to me and I decided that my power is fine...I need the mpg right now....try switching the filter back and do another mileage check....good luck

Its not the k&n filter doing it. Mine improved my overall mileage a bit
 

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saltydog said:
i guessing that it's the winter fuel
I agree with the winter fuel theory as I always reset the trip counter and need gas way earlier than in the warm weather. Close to 40 miles less per tank. Isn't it great they raise the price and we get less energy from the gas.

Clint
 

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The system does take time to learn new a/f mixtures. That happened with my K/N.

I wonder what would happen if you put in octane boost?
 

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Octane boost cost too much to consider using. Add its cost to a tank of gas then divide by gallons bought to see the new cost per gallon for fuel.

Clint
 

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Reid Roeske said:
Hi all, I have a 2004 Titan, w big tow, and off road packages. I had been getting 14 - 15 mph until about 3 mths ago, then it started to drop to around 11 on the highway, with the recent low of 8.6! It's been to the dealer twice, first time they said the air flow sensor needed an "update" which they did. No change, second time they see nothing wrong on teh computer. I have changed teh air filter (k/N), air pressure in the tire @ 40 lbs, and have changed the oil. The dealer doesn't know what to do, and neither do I. It's getting to the point where I might have to get rid of it.

Has anyone run into this, and more important, any solutions? I'll try anything, I like the truck, and don't want to get rid of it. Thanks!
Try resetting the ECU?

http://www.titantalk.com/forums/titan-faq-howto-area/25118-how-ecu-reset-throttle-accelerator-position-learning.html
 

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anmut said:
I was told resetting by disconnecting the battery will kill any timing advance on the 2008.
This isn't disconnecting the battery and there is a matter of opinion about that.
 

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Discussion Starter #12
Thanks for the replies so far. In answer to some of teh questions..
1. I have not switched gas stations, and I noticed this problem in Sept, I assume way too early for "winter gas"

2. I switched to the k/n filter after I noticed the mileage falling

3. I tried resetting the ecu about 2 months ago (from this forum)

It has been mentioned to me that a bad fuel filter may be the cause. I was told there may be two filters, one being a return? Thanks again for the brainstorming.
 

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Where do you live? If you're in the NE states, there is no winter gas anymore. It's all 10% blend. I'd try a stock air filter if that's all you've changed. 105k plugs so...they should be fine. 8.6 MPG without towing ? I'd say there's definitely a problem. My 04 is closer to 13-15 around town with no upgrades or updates to the ECU or any sensors. An 02 sensor on the way out maybe?....no idea.
 

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another thought. Have you checked to see if you have a sticking brake caliper or parking brake? The other obvious stuff I left out because you said in your first post that you took it in 2 times to the dealer. If the tech has half a brain he would have checked those things out already (fuel filter, injectors, tires, brakes, MAF, etc) but we all know that most of them dont have half a brain so you may want to dump a can of complete fuel system cleaner in the next tank to see if that helps. :poke:
 

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I thought I read somewhere in the manual that it said the Titan will never need any type of fuel system cleaner ever? :dunno: I don't remember the logic behind it, but I do remember something like that catching my eye when I was reading through the manual when I bought the truck.
 

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Happened to my 04 once. I thought it was the gas station I switched to. A week later, I got CEL on with a code P0456 (not sure the #). Dealer said my Evap system leaked and they fixed it. After that the mileage went back to normal.
 

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Discussion Starter #18
Interesting thought on the hanging up parking brake. I had the pads ont eh parking brake on the drivers side go out about 2 mths ago. My local station that I trust just pulled off teh pads, said that would be good enough for teh parking brake, and save about 200 bucks for pads. I wonder if something goofy is going on on teh passenger side.

As for teh dealer, I think all they did was plug it into teh computer, computer says OK, must not be a problem!? Thats kinda why I posted here, looking for things the computer might not show. Biggest problem is dealer is 2 hrs away, tough to keep running there to "test" stuff.

Heres something else I forgot to mention. I had it into teh local shop to fix radator leak, and had them plug it into their magic box. They said that it was reading that it was running lean. They said that didn't make sense, that with bad gas mileage it should be running rich. They said that even when they spiked the acceclerator it still showed lean, and should read rich for a brief moment. That raise any flags w/ anyone?
 

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Juday said:
I thought I read somewhere in the manual that it said the Titan will never need any type of fuel system cleaner ever? :dunno: I don't remember the logic behind it, but I do remember something like that catching my eye when I was reading through the manual when I bought the truck.

yeah when I bought my truck the salesman tried to tell me 3 things.

1. the spare tire was a doughnut

2. NEVER USE PREMIUM FUEL!!!

3. NEVER PUT FUEL INJECTOR CLEANER IN THE TANK!

with that said... if your performance is getting bad a little can of STP won't hurt anything every 5k miles or so.:cheers:
 

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This might off topic but this might help to some extent.



TIPS FOR PUMPING GAS

I don't know what you guys are paying
for gasoline, but here in California , we are also paying higher, up to
$3.50 per gallon. But my line of work is in petroleum for about 31 years
now, so here are some tricks to get more of your money's worth for every
gallon.

Here at the Kinder Morgan Pipeline where
I work in San Jose , CA we deliver about 4 million gallons in a 24-hour
period through the pipeline. One day is diesel the next day is jet fuel,
and gasoline, regular and premium grades. We have 34-storage tanks here
with a total capacity of 16,800,000 gallons.

Only buy or fill up your car or truck in
the early morning when the ground temperature is still cold. Remember
that all service stations have their storage tanks buried below ground.
The colder the ground t he more dense the gasoline, when it gets warmer
gasoline expands, so buying in the afternoon or in the evening . . .
Your gallon is not exactly a gallon. In the petroleum business, the
specific gravity and the temperature of the gasoline, diesel and jet
fuel, ethanol and other petroleum products plays an important role. A
1-degree rise in temperature is a big deal for this business. But the
service stations do not have temperature compensation at the pumps.

When you're filling up, do not squeeze
the trigger of the nozzle to a fast mode. If you look, you will see that
the trigger has three (3) stages: low, middle, and high. In slow mode,
you should be pumping on low speed, thereby minimizing the vapors that
are created while you are pumping. All hoses at the pump have a vapor
return. If you are pumping on the fast rate, some of the liquid that
goes to your tank becomes vapor. Those vapors are being sucked up and
back into the underground storage tank so you're getting l ess worth for
your money.

One of the most important tips is to
fill up when your gas tank is HALF FULL or HALF EMPTY. The reason for
this is, the more gas you have in your tank the less air occupying its
empty space. Gasoline evaporates faster than you can imagine. Gasoline
storage tanks have an internal floating roof. This roof serves as zero
clearance between the gas and the atmosphere, so it minimizes the
evaporation. Unlike service stations, here where I work, every truck
that we load is temperature compensated so that every gallon is actually
the exact amount.

Another reminder, if there is a gasoline
truck pumping into the storage tanks when you stop to buy gas, DO NOT
fill up! Most likely, the gasoline is being stirred up as the gas is
being delivered, and you might pick up some of the dirt that normally
settles on the bottom.

Hope this will help you get the most
value for your money.
 
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