06 Montero Ltd Gen3 - is premium fuel necessary?
- Thread starter taybrynn
- Start date
Rambo Penguin
Member
For what it’s worth, I’ve only ever run regular in mine and don’t have any issues haha.
jeep-N-montero
Expedition Leader
Simple answer is yes. Complicated answer is that even if it was not "required" the vehicle runs better on premium due to less knock and more advanced timing, read up on it and you will learn a bit.
Doing_Dirt
Active member
I can't imagine premium in the bush or jerry cans. Monteros (Pajeros) have been all over the world... I doubt premium was needed. 
DetroitDarin
Scratching a 10 year Itch
Remember, higher octance gas is harder to burn. (shrug) - the fuel itself is mislabelled as 'premium' as if the gasoline itself is somehow better. Seems lately octane is gold because adding some to a gallon of gas can change the price by $.50. Unreal.
As a weird thing/story - for my RX8, when I use 93octane fuel I get about 14mpg. When I use 87 I get about 17-18mpg. (shrug).
If you're not getting detonation, and if the ECU isn't advancing timing more than it would with 87 Octane, there isn't a lot to stress about. Maybe try midgrade and see how the truck runs?
As a weird thing/story - for my RX8, when I use 93octane fuel I get about 14mpg. When I use 87 I get about 17-18mpg. (shrug).
If you're not getting detonation, and if the ECU isn't advancing timing more than it would with 87 Octane, there isn't a lot to stress about. Maybe try midgrade and see how the truck runs?
coffeegoat
Adventurer
Did they remove the knock sensor when they transitioned to the 3.8 engine? I know my 3.5 has it (2001), but I'm not terribly familiar with the 3.8.
I ran some experiments with my 3.5L and couldn't find any discernable difference between regular and premium, though on an older vehicle "plus" definitely made a difference. However, since then I've replaced the oxygen sensors and seen better mileage, so it may be reworth running the tests. You can do a couple of runs to determine if the improvement in mpg is worth the cost difference. Supposedly there would be a slight HP increase, but again, I didn't see any...
PajEvo
JDM Journeys
I run 91 in the PajEvo. It has higher compression than the regular non-mivec 3.5L and needs the higher AKI. Esp when it's just begging you to rev it.
But on our last 2003 3.8, I only used premium when towing, to eek every little bit of available power from it. Perceived or otherwise.
I'm at altitude, so my 91 is equivalent to about 94 or so at sea level.
But on our last 2003 3.8, I only used premium when towing, to eek every little bit of available power from it. Perceived or otherwise.
I'm at altitude, so my 91 is equivalent to about 94 or so at sea level.
Toasty
Looking for that thing i just had in my hand...
Pretty sure the 3.8 has a knock sensor but i don't own one anymore to check, but i run premium in all my machines even the ones that don't recommend it. When my homies get to drive my rigs they always comment on how solid and powerful they run, so consider that.
The 3rd world didn't get these more powerful engines, most of the more developed countries didn't get the 3.8 until 2007 either. Having said that, they run just fine on regular (even the DOHC) but give it what it wants the majority of the time and it will serve you better longer.
I can't imagine premium in the bush or jerry cans. Monteros (Pajeros) have been all over the world... I doubt premium was needed.
The 3rd world didn't get these more powerful engines, most of the more developed countries didn't get the 3.8 until 2007 either. Having said that, they run just fine on regular (even the DOHC) but give it what it wants the majority of the time and it will serve you better longer.
Doing_Dirt
Active member
I notice the difference from our 87 vs 91 octane. I switch back and forth when I can really afford premium when its under $3.99/gallon.
Doing_Dirt
Active member
We should be so lucky. I would put premium in everything including the lawn mower!
I believe there are other ways besides the knock sensor for the ECM to detect knock. Can’t think of it right now but when it comes to me I’ll post it up. I think it can be seen with the crank-cam sensor data. Similar to detecting a misfire. I wouldn’t relate the absence of a knock sensor to determine what fuel you should run.