I am only getting 175 miles per tank before my gas light comes on. I have 265 75 16 bfg. Is this normal? I am pretty sure I was getting a lot more than that before I put the BFG on. I was prepared for it to make a difference but not this much. It is not bothering me enough to make me want to sell it but if there is something that I need to do or am not doing please advise. I drive an 02'
Gas Mileage question
- Thread starter sippicruiser
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Welcome to the Mud!
How long have you owned the cruiser and what kind of maintenance history does it have? I agree that something seems off. You shouldn't be getting such low mileage with tires that small, even if they are BFGs. First and foremost, what is your driving style like? I have found that romping on these rigs will eat tons of fuel, so if you drive aggressively you'll see very poor mileage.
On the maintenance side, I would start with the simple stuff first. How is the air pressure in the tires? How does the air filter look? What kind of gas are you running and which octane are you using?
From there I'd check the MAF sensor. I've found that even if it looks clean, there could be an invisible film of dust/crud on it. Buy some MAF sensor spray cleaner and spray it off. Do not touch anything to the wires or try to physically wipe them off. Just spray the cleaner onto the sensor wires, let it dry thoroughly, and re-install. I pciked up about 1-1.5mpg after cleaning mine. I'd also check for intake/vacuum leaks while your in there. Is the truck running ok? The more information you provide, the easier it is for us to make recommendations.
How long have you owned the cruiser and what kind of maintenance history does it have? I agree that something seems off. You shouldn't be getting such low mileage with tires that small, even if they are BFGs. First and foremost, what is your driving style like? I have found that romping on these rigs will eat tons of fuel, so if you drive aggressively you'll see very poor mileage.
On the maintenance side, I would start with the simple stuff first. How is the air pressure in the tires? How does the air filter look? What kind of gas are you running and which octane are you using?
From there I'd check the MAF sensor. I've found that even if it looks clean, there could be an invisible film of dust/crud on it. Buy some MAF sensor spray cleaner and spray it off. Do not touch anything to the wires or try to physically wipe them off. Just spray the cleaner onto the sensor wires, let it dry thoroughly, and re-install. I pciked up about 1-1.5mpg after cleaning mine. I'd also check for intake/vacuum leaks while your in there. Is the truck running ok? The more information you provide, the easier it is for us to make recommendations.
I would say you are about 100-125 miles short of what everybody else is getting. I would definitely get that looked at. There seems to be an improvement gain from cleaning your Throttle Body and Mass Airflow Sensor: https://forum.ih8mud.com/100-series-cruisers/216636-maf-tb-plate-cleaning-pics.html
- Thread starter
- #4
I do not drive aggressive at all. I am also not very well educated in the mechanic field so please excuse my ignorance. I am due an oil change so I am going to start there and get them to replace my air filter. It runs fine and I use 91 octane. Is it easy for me to check my MAF sensor? Thanks for your response and advise.
Winter I get 225-270 and I never let the gas light come on...Summer, 250 - 325 miles. Very unscientific, depends on a lot of factors.
I just cleaned my MAF and Throttle Body...use the "search" - both are very easy/simple.
I just cleaned my MAF and Throttle Body...use the "search" - both are very easy/simple.
You've either got an extremely dirty MAF or you have between 120K and 140K miles on your truck and you're less than 1000 miles from throwing a Check Engine Light for a faulty front O2 sensor. The MPGs drop WAY off before they go out completely and trigger the CEL. Read up on Denso replacements. $60 on Amazon instead of $160 @ the dealer.
- Thread starter
- #9
My air filter was clean. I called a local mechanic who works on Toyotas and he said that if the O2 sensor is needing to be replaced my CEL would have come on. Is this always true? I have looked at the instructions on cleaning the MAF and I honestly do not feel comfortable doing that myself. How much does it usually cost for a mechanic to do it? Thanks again for everyones advise.
It's a 5 minute job plus a half a can of CRC MAF cleaner from Napa. My
could do it - don't be intimated by it being an electronic part. The MAF comes out of the intake just south of the filter. With the engine off and key out, disconnect the harness. Pull the screws, it comes out vertically upward. Place a cloth under it to collect the drips. Spray down the three wires. Keep in in roughly the same vertical orientation so that the drips run down and not up toward the head. Let it dry thoroughly. Replace and 
happy!
it's a 5 minute job plus a half a can of crc maf cleaner from napa. My
Remember: Do not touch the wires on the MAF!!!
Sippi, I'd like to reiterate how simple it is to clean the MAF yourself. However, if you truly aren't comfortable doing it, theres no shame in taking it to a shop that can do it for you. They will charge you much more than you'd pay doing it yourself, probably in the neighborhood of $50 for a 5-10 minute job, but that is much better than doing something you aren't comfortable with and risking damage to the MAF.
This thread has got me wondering about my 02 sensors since my mileage sucks despite my driving like grampa jones. I'm right on the high side of the mileage range at 136K. Might be time to peruse Amazon...
This thread has got me wondering about my 02 sensors since my mileage sucks despite my driving like grampa jones. I'm right on the high side of the mileage range at 136K. Might be time to peruse Amazon...
I'm telling you guys... On a Toyota Truck, if you have a sharp mileage economy decrease after 120K, it's *most likely* an O2 sensor that's on it's way out, but isn't so far out of spec to trigger a CEL. Kind of like when the MAF or Throttle Body gets dirty, but not dirty enough to trigger the CEL... Same principle applies. There's a RANGE to the specified performance which is reported to the computer as a control signal, and as long as it's in that expected range, whether wrong or not, then the computer won't know any different. Also, the O2 will be OK for a while, then one or two tanks you might drop 20% or more on MPG's, then it might jump back up or stay where it's at. They're funny like that. When a MAF or TB gets dirty and loses performance, you don't see a dramatic drop, but one that slowly degrades over time.
I've had THREE toyota SUV's do the same thing, and almost identical mileage. This has been my experience over the last 7-8 years and others report similar things. I'm just offering my observations to help you pinpoint the issue.
The moral of this story is "don't overlook checking the O2 sensors with a multimeter just because you don't have a CEL".
As a front O2 sensor is on it's way out, the control signal will not be where it should. The engine will base the fuel mixture on the feedback it gets from the O2 and the amount of air it senses across the MAF. The throttle body is what controls the amount of air allowed into the engine. That's why these things are so critical in fuel economy. The computer uses the O2 sensor to adjust the fuel mixture so that there's a small bit of oxygen and unburned fuel exiting the cylinders to get a secondary "burn" in the catalytic converter and reduce the NOX emmissions. When the signal begins to go out, it doesn't sense the unburned fuel as well as it should, and the computer thinks the engine is running lean, enriching the mix. When this happens, you consume more fuel than you should, and you might even be able to smell it in the exhaust if it's REALLY out of spec. The thing that eventually triggers the CEL is usually when the heater circuit (for start-ups) goes out on the MAF, and not a faulty signal.
Posted this @ 10/27/2009:
In April 2010, I got a CEL:
I've had THREE toyota SUV's do the same thing, and almost identical mileage. This has been my experience over the last 7-8 years and others report similar things. I'm just offering my observations to help you pinpoint the issue.
The moral of this story is "don't overlook checking the O2 sensors with a multimeter just because you don't have a CEL".
As a front O2 sensor is on it's way out, the control signal will not be where it should. The engine will base the fuel mixture on the feedback it gets from the O2 and the amount of air it senses across the MAF. The throttle body is what controls the amount of air allowed into the engine. That's why these things are so critical in fuel economy. The computer uses the O2 sensor to adjust the fuel mixture so that there's a small bit of oxygen and unburned fuel exiting the cylinders to get a secondary "burn" in the catalytic converter and reduce the NOX emmissions. When the signal begins to go out, it doesn't sense the unburned fuel as well as it should, and the computer thinks the engine is running lean, enriching the mix. When this happens, you consume more fuel than you should, and you might even be able to smell it in the exhaust if it's REALLY out of spec. The thing that eventually triggers the CEL is usually when the heater circuit (for start-ups) goes out on the MAF, and not a faulty signal.
Posted this @ 10/27/2009:
In April 2010, I got a CEL:
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Makes sense to me, and funnily enough I have commented to my wife twice now about how rich the exhaust smells. Would extra unburned fuel screw up emissions though? Because my cruiser passed with flying colors...but the fuel smell in the exhaust is undeniable. Off to Amazon I go. $106 wont kill me even if it doesn't completely solve the issue. It'll be good to replace them anyway.
I just installed 2 pre-cat O2 sensors in mine this weekend. I bought them from Amazon. Below is the part number I used. They were 55.46 each.
2 Denso 234-4169 Oxygen Sensor (Air and Fuel Ratio Sensor)"
Automotive; $55.46
What is the Toyota recommended O2 replacement interval on the 100?
Mine gets 14-16 mph. I have not taken it on a road trip yet. I drive like grandpa 90% of the time.
Mine gets 14-16 mph. I have not taken it on a road trip yet. I drive like grandpa 90% of the time.
