I've had it with this horrible Gas Mileage! Idea's?

[Joe_Black]

Joe, is there a way to check the canister for functionality/damage to see if it needs replacing?

I've attached an Acrobat file of some various info regarding excessive fuel consumption from the service manual. Y'all should find it interesting, especially the component locator table.

[DK]

I posted a couple of months ago that my mileage dropped from 16.5 to 13.5 immediately after I had my 30,000 service at Sierra. Today I took the VX in for them to check things like the 02 sensor.

Here's what found:''Diag fuel ratio in specs, 025 sensor in specs...no problem found - performed scan tool diag -- found no DTCS -- all fuel trims in spec -- fuel ratio is right on -- 02 sensors working correctly"

Looks pretty thorough to me. No problems identified.
Am I correct in assuming that if some of the things mentioned above -- pinched lines, etc. -- were the cause this would have showed up in the testing?

So other than brake drag or flat tires, what else could it be?

Question: if the brakes were dragging enough to reduce my mileage that much would I not notice excessive heat and some kind of burning smell?

[Numba1goalie]

Update: When i first started this thread I was fresh with a new tank of gas and apparently the VX heard my growling and got 355 miles to the tank.

Now with a new fill up, I'm at half tank and only have 134 mile sont he odemeter. Here we go again I guess.

I am ordering a new intake manifold gasket soon along with some other things.

[VehiGAZ]

And here I go again - Goalie, before you go ordering parts, please - finish the mileage experiment. Don't do any math with the fuel gauge - it's only accurate to maybe +/- a quarter of a tank of gas, and you even said in a previous post that itt was showing only an eighth of a tank left, but only 11 gallons went in.

If you don't have the patience to wait until you finish this tank of gas, then go ahead and fill up now just like you did the last time when you reset the trip odometer and DO THE MATH... divide the number of miles showing on your odo by the number of gallons you just put in your tank, and that will tell you your true mileage. By the numbers you yourself posted before, you are getting over 19 mpg! (210 miles on 11 gallons of gas... 210/11 = 19.09).

Make sure you have a problem before you try to fix it. Problems that aren't really there have an annoying way of not responding to fixes.

Good luck!

[nater]

You know, have you changed your driving style/ route/ schedule lately? Bad traffic, lots of starts and stops, even aggressive driving can affect your mileage.

I noticed when I worked late for a week that I got better mileage. (The drive home had almost no traffic).

Nate

[Joe_Black]

^^^^ Heed what VehiGAZ is saying, good advice! ^^^^

[Numba1goalie]

I notice real bad fuel economy mostly on the highways over 70 mph. which is about 2800-3000 rpms.

I am still following your advice though, I am just giving it a few tanks to get the average number. I feel like im in a Math class again. lol.

[SPAZZ]

I installed my new Fuel pressure reg yesterday. Pathetic how small that thing is. My idle is more regular now instead of so high and it seems to start easier.

Hopefully my mileage will gain from the new one.

[WyldWeasel]

A Thousand Pardons if this is a stupid question, but wouldn't driving with the Power button activated affect mileage? The location of the button is such that it could accidentally (or purposefully) be depressed by a passenger without the driver's knowledge.

[JAFO]

A Thousand Pardons if this is a stupid question, but wouldn't driving with the Power button activated affect mileage? The location of the button is such that it could accidentally (or purposefully) be depressed by a passenger without the driver's knowledge.

I always drive with the power button on. I get 18 mpg.

[Joe_Black]

A Thousand Pardons if this is a stupid question, but wouldn't driving with the Power button activated affect mileage? The location of the button is such that it could accidentally (or purposefully) be depressed by a passenger without the driver's knowledge.

Most Isuzu owners report that the POWER setting usually gives the best overall economy, and this is across the Trooper/Rodeo/Amigo/VehiCROSS line. Additionally, there is an illuminated indicator on the instrument cluster to let you know when the buttons are set to anything other than NORMAL. In a nutshell, the different modes adjust the shift points and torque-converter lock-up profile to suit your driving style or conditions.

[DK]

I just put 600 plus miles on the VX this past weekend with a trip to Twenty-Nine Palms and through Joshua Tree National Park and around the Salton Sea.

My mileage went from 13.5 to an average of 20 mpg -- much of it with the air conditioner on.

What did I do differently? I increased the tire pressure from 32 to 34 psi. Original wheels and tires. Amazing.

[VCAMILO]

Do what I do... I live 3 miles from work. Drive the GF's 350Z and when Im Im boared I hop on the TL1000R. Pretty much use the VX to drive to work, get groceries, quick trip to HomeDepo, restaurant, and go Quading on Sundays. LOL! Soccer mom car! 52k miles and counting

V

[DOCSXV]

First, Use the right plug: NGK laser platinum ONLY it runs like crap without them and eats too much fuel with any others ( Yes I know there $10 each, just buy them).

Second, clean the mass air flow sensor, nobody ever thinks of it and it ALWAYS adds MPG. Just make sure you buy the right stuff its called um.. mass air flow sensor cleaner; while your at it put in a new filter.

third, rid yourself of the factory fan and opt for an electric one.

fourth, turn TOD off and install some manual hubs.
I average 18-19 MPG with 20-21 (maybe 22 if theres a stiff wind to my back) MPG freeway, with these mods.

Doc.

[Amnesia]

Ok - Since this thread is alive again, I'll add an update. Back when I originally posted in '06, I had just shy of 100K miles... Well it's more like 160k miles now. My mileage is up around 17.5 to just shy of 19 usually these days. (I'm not fanatical about my tire pressure and when I add air, I run them around 34-35psi. I think I may boot them to 39 & see what happens.)

The valve cover fix I mentioned. It was covered by warrantybynet.com, but didn't solve my oil consumption problem. (It sometimes uses a lot... other times not so much. Still not solved.)

The intake gasket. I fixed that myself last summer after I was fed up w/ getting 12-13mpg. READ: 250ish miles per tank w/ 20 gallon fill-ups. **Note: Mileage calc lessons were humorous. Thanks! (No offense) After I replaced the gasket, my milage went up to the 16-19mpg range.

To check for an intake leak, just take a can of carb cleaner and spray it along the intake-to-cylinder head mating surfaces while at idle. If the idle goes up or changes, then you have found your leak.

The brake drag... Yes, you will feel the heat and smell them if they are dragging very much.

I would also suspect the fuel gauge is wrong, goalie. Mine is definitely messed up now. The needle is all over the place once the level drops from a totally full tank. Sort of like if the tank didn't have any baffles and the fuel could slosh all around, letting the float rise and fall too much.

Ok - That's all! Best to everyone!