Gen 2 or 2.5 MPG?

[raysobi]

Hello All,

It had been a year since I bought this lovely SUV and I still love it just like the first day bought her.


However; I am questioning the MPG claimed:


MPG: 16 city / 19 highway
Towing capacity: 5,000 lbs
Horsepower: 200 HP
Engine: 3.5L V6
Fuel tank capacity: 24.3 gal

I also saw some of the member in here bragged about they got as much as "23 MPG", and I was wondering...Did I Monty wrong all these time?


My Monty has about 84K miles, Synthetic Oil is changed regularly. Timing belt and spark plugs were changed 10K ago.

The average of my MPG is around "250 miles" which translated to roughly 10~ MPG with 33x10.5.15 all terrain tires.
Is it something wrong with my truck? I had tried driving it with 2WD, and 4 WD but it doesn't matter. Maybe when I changed the Spark Plugs, I didn't do it correctly?

I am not expecting to get Prius MPG but 10 MPG is a bit weird IMO, and trust me, I don't have a heavy foot.

 

[PacS14]

Are you going off the trip meter on the cluster? Remember now with bigger tires MPGs will go down not just because of the added weight but the trip meter on the cluster is off. With my new tires I saw that for every 2 miles the trip meter kn the cluster reads 1.5 miles. Also how fast you take off, stop and go, how fast you keep it on the highway will affect all this along with how much pressure you got on the tires. Overall the best thing to help your MPG go up will be your right foot. It's too early for me to tell but I would check that along with a gps speedometer that has a trip feature.

 

[speedtre]

Well if you are using the tripmeter to calculate you MPG then you have to factor in that your tires are 12% bigger so your actual mileage is closer to 250 x 1.12 = 280 MPG. That is still pretty low but with stock gearing, that much of a tire increase will greatly decrease your mileage, especially if you do alot of stop and go driving. My '99 with 31x10.5x15 (5% larger than stock) gets about 16 MPG (15 by the tripmeter). Mine is a DD and I would say 80% of it is city stop and go driving. When I take her on longer road trips which are more like 80% highway she pulls 18-19 going 75-80 MPH. If I kept it around 60-65 mph I bet I could get 20 mpg.

 

[Toasty]

Also if you never regeared for the bigger tires you're making the truck work harder to do it's job.

My 1999 Gen 2.5 i very easily get 15MPG in town and about 17MPG on the highway and i have 35" tires and armor. Keep in mind i have manual hubs and my truck is geared to 4.90:1 in the axles and my speedometer is spot on. This milage is pretty typical, we averaged about 14MPG on the Sierra Challenge in a fully loaded 1994 Montero 3.5 DOHC on 35" tires.

 

[jeep-N-montero]

Dude, it's a heavy SUV with bigger/heavier tires on it built for fun, who cares about MPGs??

 

[raysobi]

Also if you never regeared for the bigger tires you're making the truck work harder to do it's job.

My 1999 Gen 2.5 i very easily get 15MPG in town and about 17MPG on the highway and i have 35" tires and armor. Keep in mind i have manual hubs and my truck is geared to 4.90:1 in the axles and my speedometer is spot on. This milage is pretty typical, we averaged about 14MPG on the Sierra Challenge in a fully loaded 1994 Montero 3.5 DOHC on 35" tires.

This sounds very logical to me, and I think gearing part really make sense.

Thanks for the replied.

 

[raysobi]

Dude, it's a heavy SUV with bigger/heavier tires on it built for fun, who cares about MPGs??

This truck is my DD, and I did about 50/50 city highway.

Gas is really cheap here in Houston, especially at 1.70/gallon as of now.

However, I thought it was something wrong with my truck since I saw "drastic" changed in MPG with new shoes.

 

[raysobi]

Also if you never regeared for the bigger tires you're making the truck work harder to do it's job.

My 1999 Gen 2.5 i very easily get 15MPG in town and about 17MPG on the highway and i have 35" tires and armor. Keep in mind i have manual hubs and my truck is geared to 4.90:1 in the axles and my speedometer is spot on. This milage is pretty typical, we averaged about 14MPG on the Sierra Challenge in a fully loaded 1994 Montero 3.5 DOHC on 35" tires.

Toasty,

I have an app called Torque that I uses to diagnose my engine code. It is communicating through Bluetooth OBDii adapter. It also had a feature that allows me to track my trip through Google map with analytical stuff that I haven't played with.

I will give it a shot.

How do you like a new gearing ratio so far?

 

[Toasty]

I will never go back to incorrect ratio for tire size again, with 33's you should swap in some 4.63's from a mid 90's Montero. Look for a 94-96, the '94 you will need to swap pinion flange but all else is a bolt on deal. Plus you'll get a locker.

 

[PacS14]

This is where I'm at and I live in Houston too, but most of my driving is highway with little to no stop and go (odd schedule), like I said I slowly work my way up to speed, not snail slow but nothing like I would with my 240sx.



This is the first full tank on the 33" tires and already past the 10 MPG that you are getting. The next thing on my list is to install the manual hubs and look for a scan gauge. I know about the Bluetooth devices and all, but I'mnot too kin to have to multi use my cell for mmultiple things while driving.

 

[quailchaser]

You should be getting much better than 10. My 98 got 19 Hwy when I first bought it. I switched tires from a lower rolling resistance highway Michelin to the M& S Michelin. I lost 2 to 3 mpg from that alone. On a previous truck (Ford) I went from C rated tires to E rated and went from 17mpg to 14mpg. Tires do make a difference, but not down to 10mpg. I would check the accuracy of your speedometer/odometer and how your engine is running. Check the pcv valve, etc.

I'm rebuilding my 98 at 205,000 miles. It still got 15mpg in town, but was using and leaking oil. Diagnosis was worn seals, worn camshafts, and one bad exhaust valve and still had full compression and got the 15mpg with these issues. I'll post how it does once it's back together.

 

[raysobi]

You should be getting much better than 10. My 98 got 19 Hwy when I first bought it. I switched tires from a lower rolling resistance highway Michelin to the M& S Michelin. I lost 2 to 3 mpg from that alone. On a previous truck (Ford) I went from C rated tires to E rated and went from 17mpg to 14mpg. Tires do make a difference, but not down to 10mpg. I would check the accuracy of your speedometer/odometer and how your engine is running. Check the pcv valve, etc.

I'm rebuilding my 98 at 205,000 miles. It still got 15mpg in town, but was using and leaking oil. Diagnosis was worn seals, worn camshafts, and one bad exhaust valve and still had full compression and got the 15mpg with these issues. I'll post how it does once it's back together.

Thanks Quail,

Obviously it was a lack of understanding on my part as well on how the odometer work vs non factory tire specs.

 

[PacS14]

Thanks Quail,

Obviously it was a lack of understanding on my part as well on how the odometer work vs non factory tire specs.

How many miles per tank are you getting according to the cluster?

 

[raysobi]

I put on full tank, track odometer and until refuel light shows up at 255 miles.

 

[PacS14]

I put on full tank, track odometer and until refuel light shows up at 255 miles.

This is my first full tank with the 33" tires I will see how I do and report back. Should have a number back to you before the end of the week. It will have a margin of error since my wife has driven it a few times and she did not have my phone to run the gps speedometer. Hence why I will be looking for a scan gauge.