14.7

That's what I averaged per gallon my last tank of gas. I think I get the worst mileage out of anybody on the board.

My Rodeo is completely stock:
Tire pressure is perfect
spark plugs are less than a 1.5 years old
same with fuel and air filters
IMG is fairly new
EGR gets cleaned regularly as does PCV
Throttle body is clean
have a new O2 sensor at bank 1 sensor 2
bank 1 sensor 2 is less than 1.5 years old
both catalytic converters are "new"

I checked for brake drag, that's not the problem

I don't drive like I stole it, but I don't drive like my grandmother either.

I don't know where else to look.

I am not complaining about poor mileage because gas is expensive, I am worried there is a serious problem. I've had the Rodeo for two years and the mileage has always been bad. My mechanic says it may be the gearing, he wasn't sure about Isuzu and what they offered. Is it possible I have different gears from others who are getting better mileage? I doubt this is the case, but it is a theory at least.

The Rodeo runs great and I have asked this question before, I may even have a thread about this on here. Another won't hurt I hope.

I am at a loss, it just confuses me as to why I get this consistant, low MPG. I see post by all others on the Isuzu boards and it seems as if I'm way below.

Any ideas where to look?

marc

all city miles?

Marc, that intake air temp sensor would do it. A dirty MAF will kill your mileage as well. I'd replace that IAT sensor if you havent, and I'd clean the MAF.

Joel

Mine's hangin about 17mpg in city; I think it's the MAF sensor on mine that keeps tripping the CEL. It comes on for 2 days and goes off for 3, comes on...you get the picture.

Couple things, is the 14mpg all city? Lots of stop and go? If so, this could be about the best you'll get.

Another thing, has the rear differential fluid ever been changed?

thanks for the replies fellas.

a couple of things:
Rear diff has been changed last fall
I'd say mostly non stop and go with a lot of highway, but short trips.


Joel,
the IAC has only been broken for a month, bvut it does not effect the performance. It is broken in the outside housing, but the connector still attaches correctly.

I am going to clean the MAF, even though I do not want to touch it, ther are fuzzies all over it. It can't hurt, unless I break it, LOL.

I am seriously thinking I just have a vehicle that does not get good mileage.

The best I've ever gotten was 18, but that was once. Most of the time it is in the 15's to low 16's.

marc

I was getting a steady 15mpg all winter. Got 16.5 on the first tank of non winter gas. The last tank I got on it a few times and was back down to 15 again. Mine is all just going to work and back (8 miles each way) but its mostly on I-225 so the same as city driving, only get up to highways speeds for 2-3 miles.

I dont remember what gear ratio mine has. Its printed on one of the tags bolted to the rear axle housing cover, if your tags are still intact.

Btw, I have synthetic in engine, trans, xfer, and axles. Didnt see any gain in mileage. But then theres no point in having 205 hp if you dont use it right?

I'll be doing plugs and cleaning MAF in the near future so will see if mine improves any.

My 2000 averages 15 in the city... seems to be pretty average with this model.
could be the gearing, it was one of the the fastest suv's (0-60) in its class in 2000 and actually still is.
I average 22mpg on the freeway.

http://www.albeedigital.com/supercoupe/articles/0-60times.html

http://www.car-videos.net/performance/view.asp?id1=30&id2=0

Macre - what oil viscosity are you running?

I agree with the idea that synthetics don't give any better gas mileage over regular fluids; but one viscosity to another will, i.e. 5w-30 versus even 10w-30. Reason for that, mainly in winter/cold season, is the 5w will get thru your engine faster and warm up faster when it's cold. There won't be more then a 1-2mpg difference though - but anything may help.

In temps above 50F, there's no difference in mileage gain between those 2 viscosities.

I threw in 5w-40 this last oil change, and my mpg has already dropped 2-3mpg; didn't experience this last summer though. But I think because the tune-up brought the mileage back up, and then I threw a heavy oil in it, and now it shows.

Hi Marc,
The best mileage my Rodeo Sport ever got was 22 mpg. This was on a
straight shot from Sacramento to Bakersfield..... a long boring flat surface.
The average speed was 65 mph with the top down.
However when I used to commute from Sac to San Fran Bay Area at 80 mph
I averaged 19mpg. I think speed & tire pressure made a difference.
BTW....... I assume your tires/ wheels are stock?
I do notice that she runs smoother requiring less foot right after an oil change.

I'm using 5w 30 pennzoil blend. I guess I'll have to learn to live with this, but it's annoying.

My main concern is that everything is OK.

marc

I got 17.2 on my last tank and 16.5 on the one before that. I hope it keeps creeping up, gas was $2.96 today. OUCH!!!!!!

75W90 Mobil 1 synthetic Gear Oil in both differentials. Yes, the front one, too.

GM AutoTrak II in the NPG transfer case (the new variety "II" is also synthetic).

Do some tribology research, learn about polymers as VI enhancers, and you'll break your habit of Quaker State/Pennzoil for good. Try a more highly refined base stock oil like Valvoline or Shell. Or better yet, check into PAO synthetics instead.

Checked the alignment lately? Excessive toe can kill mileage.

Is the odometer correct? Oversized tires or a poorly calibrated speedometer can give the impression of poorer than actual mileage.

Is the EVAP system intact? And EVAP system that doesn't seal and recover vapors can lose 7% of its liquid fuel volume in a week in warmer temperatures.

Even though the cats are new, is the rest of the exhaust system intact?

Blue Bowtie,

Alignment was done in November.

The exhaust is mostly new, the muffler is original, but intact.

I use synthetic blend in the diffs as well as the transfer case.

Tires are correct size and correct pressure.

As far as the EVAP system, I don't know, but I have no CEL on.

The odometer is good as far as I know.

I use Pennzoil blend, I'd switch though. I have used Valvoline high mileage in the past, I may go back to it.


thanks for the reply,
marc

On vacation last month I got 20mpg. Usually, I bump the tire pressure up a bit, I think 28 lbs is too low (recommended). All synthetic fluids(Amsoil) including Series 2000 0W-30 oil year round.

Tom, good point on the tires & tire pressures. My 2002 spec'd 26psig all the way around! :uhoh: When gas hit close to $3/gal I bumped them up to 30-32psig. Marc, another huge MPG factor is the tires themselves. What brand/type of tire are you running. Aggresive tread tires suck for MPG's. I'd go for a good hywy tread tire. Synth motor oil wont increase MPG's for the 3.2L, but it certainly wont hurt. I saw a slight MPG gain running 5w-20 in my 2002 3.2L. She ran as smooth as butta on it as well. You can run GM auto trak II xfer case oil, but I wouldn't waste the $. You'd be better off with M1 5w-30 or 0w-30 in there. I'd concentrate on the tires for your MPG woes.

G/luck
Joel

I've got Nokian WR-SUV's for tires. They are six months old, so I can't replace them. The tread isn't real agressive, but they may hurt my MPG. I never thought of them hurting, but I bet it is possible.

Marc, those are good tires. Pretty much rules that out. Just be sure to keep them aired somewhere between the door jamb label and the sidewall specs. I wouldn't go over the sidewall specs.

G/luck
Joel

maybe I will go above what the door jamb says. I'ver always kept them at 29psi. I will up it a little.

Marc, I used to be the same way. Kept mine ~27psig for a long time (spec says 26). Didn't care for the tire wear or MPG's, so I went up ~4psig. You could safely go to 31-32psig on yours without issue. I'd see if that makes a difference for you.

G/luck
Joel

FWIW - I run mine at 36 front/34 rear - works GREAT.

My tire psi is the biggest factor, on my truck for crappy mileage. My door jamb calls for 29F/32R, I ran that for the longest time, and got 14-16mpg as the standard for the 1st 4yrs I owned the truck.

Then someone 5yrs ago advised me to up them a bit, even as little as an extra 2-3psi REALLY helps, ever since then, if my truck drops back to 15-16mpg even on one tank, I double check the tires 1st.

I typically average at least 17mpg with running 36F/34R - haven't noticed any adverse wear on the tires, and I discovered that I like the handling MUCH better.

I've even been known for running 38F/36R if I'm doing a lot of highway driving where tires do better with a bit higher psi for maintaining cool running. This psi is too much for an unloaded vehicle though, I usually have quite a bit of weight and/or towing the boat.

Bet you a tank of gas that if you bring your front up to 35psi and your rear up to 32psi, your mileage WILL improve.

If you have P-rated tires, the sidewalls should be safely spec'd for 35-44 *cold* psi. Don't forget to check the correct psi BEFORE driving the vehicle for the day, OR 3-4hrs after having driven 3 or more miles.

If you do check them within a short time of having drove, just make sure to leave an extra 3-4psi OVER the psi you want to obtain for cold inflation.

yes that is average for that vehicle. look at kbb.com and it will tell you

I upped the PSI from the recommended 29 up to 33-ish. I averaged 18.5 last tank. I was thrilled.

Excellent!

after the bump in PSI's, I've been hitting 18-19.5 every tank. I may go a bit higher.

I think I'm in trouble....how far can you guys go on a full tank? ( Trip odometer ) I can only go 240...and that was pushing it. Now I believe thats about 13 mpg...so now i have the worse mpg on the board!

I think I'm in trouble....how far can you guys go on a full tank? ( Trip odometer ) I can only go 240...and that was pushing it. Now I believe thats about 13 mpg...so now i have the worse mpg on the board!


give a little info about the truck and maintenance history. Year and engine size, any mods and is it 4x4?

I think I'm in trouble....how far can you guys go on a full tank? ( Trip odometer ) I can only go 240...and that was pushing it. Now I believe thats about 13 mpg...so now i have the worse mpg on the board!

Don't use the gas guage for figuring mileage, its very inaccurate, even the new one in mine isn't that great(but better than before). When the fuel light comes on, I still have around 5 gallons left, a quarter tank while the guage reads nearly empty.

I usually fill up when the guage reads 1/2 tank which is usually around 200 miles for me. I get around 15-16 mpg usually (I have a heavy foot). I need to get a new tire guage to check my tires. I think I set them to 32 PSI according to it but I think its lower.

The only reason I fill up at 1/2 tank is because this one is about twice the size of the one my mitsu had. Trying to avoid sticker shock :disappoin You should not let it get below 1/4 tank though. American fuel pumps (which isuzu used) tend to burn up without being surounded by fuel.

I have a '95 rodeo 4x4 3.2L..... i never thought about the tire psi. I will check them tomorrow. Come to think of it i have never checked them, as i have only had the rodeo for 4 months. It has these brand new tires on them, Kelley's i think. The tread is sorta like a mud tread, but shouldnt hurt that much.
I may need a new fuel pump also...its hard to start in them mornings after sitting for at least 5 hours...

thanks guys!

On that '95 Rig, HShawn31, bring the psi up a bit; the 1st generation Rodeo's are a bit heavier then the newer models.

If you're running P-metric tires, i.e. P245/70, run your fronts at about 38psi, and your rear about 36psi - AS long as the sidewall of the tire states max pressure of 40-44psi cold.

IF the max cold psi of the tire is only 35psi (I don't think it's that low, but it's been a while since I've had P-metric tires), then run front/rear at 35psi - won't hurt the tires at all, and you'll have better cornering, mpg, but the ride might be a bit bumbpier.

I have LT265/75 R16 D (8 ply) tires, and run my fronts at 38psi/rear 36 with better then average mpg for having bigger tires. When I had the 245/75, I ran the fronts at 40psi/rear 38 with excellent tread wearing and cornering.

Macre - You might be able to go to 35psi and see a tad better mpg, and if that's too much psi, you'll know as you'll find it takes longer to stop along with greater force on the brake pedal.

Gizmo42 - I thought I was the only "weirdo" who ran to the gas station at exactly 1/2 tank! Can't STAND it when it gets below that, don't know why though. But I am *knocking hard on wood* still on my 1st fuel pump.

I just got back from Baltimore(job interview) and I averaged 23.5 MPG on the way there. 21.5 on the way back. Not bad at all. Best I've ever seen on the Rodeo. I didn't burn any noticeable oil on the way there, but on the way back I was about half a quart low an hour from home. I checked several times each way just to be safe.

I will say this, it was a nice ride, pretty comfortable and the A/C did well in the 86º and very humid weather in Maryland. The ride was pleasantly smooth and comfortable.

This is the longest trip I've ever taken the Rodeo on and I was happy. For some reason I was nervous at its ability to make it. Those fears are and were unfounded.

marc

That's awesome MPG's. I dunno if I ever saw that with my 2002, but she never saw more than a ~300mi trip in one shot. Good luck with the job! Hate too see anyone have to bail out of WNY!!

Joel

My Rodeo has made several trips from SW FL to New England. All were uneventful, except for the roof rack letting go in SC at 4 am 2 summers ago. Still got all the gear inside comfortably. Ordered the part on the phone and had it wating in NH when we got there. I wouldn't hesitate to take another 1000 mile+ trip in it now.

I wouldn't hesitate to take another 1000 mile+ trip in it now.

Same here - lost count though of all the 1k+ mile trips we've gone on in the Rodeo, every single one was uneventful, with the exception of a weak clamp on the upper radiator hose 5yrs ago in Green River, Utah on one of the coldest mornings in history :eek: or at least it felt that way when you're trying to get ice cold fingers to hold a skinny clamp on a hot hot hose.