89 montero 3 liter what octane gas should i be using

The good news is that both regular and premium gas have detergents that can reduce carbon deposits to an extent. If you're buying premium, those detergents may be more powerful. Nevertheless, the key to a clean fuel system is to have your vehicle professionally serviced.

If your car is built for 87- or 89-octane gas—check the owner’s manual—upgrading to premium won’t do you any good. In fact, it could even harm both your car and the environment, since more unburned gas will get into the emissions system and interfere with its ability to prevent noxious discharge. If you’ve been using high-octane gas and your tailpipe exhaust smells of sulfur, then there’s a good chance it’s because the car wasn’t built to handle premium.

Only if car required 91 octane

Wrong spark plugs?
Make sure you use iridium plugs by NGK or Denso.
NGK V-Power Plugs BKR5E-11

Carbon Buildup?
Get some Techron and run several tanks

Wrong Octane?
Your engine should use regular gas. But you might be getting some low grade gas. You can try using a higher octane fuel. Or try adding a octane booster.

Check applicable trouble codes. Some of the national brand auto stores will check p0 codes for free. I'm not sure of engine liter size?
I looked at your owners manual, 91 octane recommended, but not required. 87 octane is ok.
Sometimes after filling up, the fumes in the gas tank are stirred up, You may have to check evap system?

yes you can use 89 octane, but at first it may seem like the car is not running right. don't worry the car is okay it is that the 89 is thicker than the 91. just give it some time.

This is a tough situation if you cannot get the vehicle indoors. That is the best course of action to unfreeze the lines. You can use an electric blanket or heating pad where practical but i would caution against any kind of open flame like a kerosene heater or even using a blow dryer.
It may not help right now but in the future if you know the temp is going to be low filling your fuel tank at least 1/2 and using a fuel line antifreeze is the best solution. In the absence of actual fuel line antifreeze, you can use 90% rubbing alcohol in small amounts (depending on fuel level but likely no more than 8oz for a full tank) to prevent freezing.

This is true. The only time you need to apply gasoline with higher octane is when preignition is present. If it sounds like marbles are bouncing in your engine when you are driving then get higher octane. However if the car is in good mechanical condition (cooling system, oil serviced regularly) then 89 octane is perfect.

Humm, give it some time. there are upper cylinder cleaners, but I worry about converter damage, and oxygen sensor damage. The lower the octane, the hotter and more masssive the burn, exactly backwards from what you would think, but higher octane is slower burn and av.gas is really, really slow.
Ford has had slow to start issues that traced back to drivers using too high octane....

Still, if it keeps pinging, you may need to run higher than spec octane.
I would have thought that your car would have knock sensor that would trim this issue...

Premium gas is still unleaded. Using a higher grade gas (ie: 89 or 91 octane) isn't going to hurt anything, and it isn't going to help anything either. You should stick to regular 87 as the higher octane rating gas isn't giving you any advantages.

Hello Joshdhorz,

The best fuel you can use on your vehicle is any octane that contains at max 10% ethanol.

Ethanol is an alcohol-based fuel additive made by fermenting and distilling crops that have been broken down into simple sugars.

A 10% blend of ethanol and gasoline will not harm any engine or fuel system component. However, the ethanol has a cleaning effect that will remove rust and other junk from the fuel system. This necessitates frequent fuel filter changes until the fuel system is cleaned out.

Most gas stations in our area are set like so:

87 octane (Up to 10% ethanol)
89 octane (Up to 5% ethanol)
91 octane (No ethanol)

Now we do not have 93 or 95 octane available to us here, so I am currently unsure as to what is in 95 octane fuels. In my opinion, I would use 91 octane (No ethanol) for the majority, while adding 87 or 89 octane (5-10% ethanol) ever so often to clean the lines.

I hope this helps you out,

Shadow

Also if you would not mind taking a moment out of your day and rating my solution it would be greatly appreciated. Thanks in advance!