V8 gas mileage with mods......horrible
- Thread starter GX4SEVEND
- Start date
You are doing the smart thing but tracking the mileage, that can be the first sign...but literally smell your car. If it smells like an old lawn mower..like any smell of gasoline at all...its rich, modern cars should not smell like gasoline.
Im not sure about dealers, sounds crazy to hand over the keys and be at the mercy of whatever some guy says is wrong and then pay top dollar for parts and labor...with advances in technology you can check your own engine codes with a smart phone and a small ODB plug in or bluetooth
Changing a sensor is not hard at all, just borrow the socket from where you buy the sensor...but the sensor itself is expensive
GX4SEVEND
New member
The rotors and pads are less than 5k miles old. I haven't smelled gas so to speak but I've noticed a natural gas smell in my garage and around my townhouse but I assumed it was from the unit next to me as it's been empty for a while and the realator just had everything turned back on.
SAR_Runner
New member
Dumb question
Ok this may be covered in your build thread ot where ever else, but have you recalibrated your speedo at all or had your battery die recently? sometimes the computer "resets" it's self and re-learns how you drive... I had this issue in my Jeep Wrangler... you might look into the O2 sensors as well as I know mine with 165K miles is definitely showing different mileage and goes through more gas than it used to.
Ok this may be covered in your build thread ot where ever else, but have you recalibrated your speedo at all or had your battery die recently? sometimes the computer "resets" it's self and re-learns how you drive... I had this issue in my Jeep Wrangler... you might look into the O2 sensors as well as I know mine with 165K miles is definitely showing different mileage and goes through more gas than it used to.
GX4SEVEND
New member
The speedo has not been recalibrated and all the measurements I've given have been just what the odometer says and what the trip computer says. Its probably 8 or 9% off. I had 35's on my 3rd gen 4runner for 50k miles and it had twice the mileage this has.
Even factoring in the adjustment, it's still pretty bad mileage
Even factoring in the adjustment, it's still pretty bad mileage
So, you have 35" tires and stock gearing? Thats most of the problem right there. The engine is struggling to move your 80lb tires with the stock gears. Until you change to 4:10's or some lower gearing, your mileage will be garbage.
FWIW-- I get much better mileage with my 87 4runner lifted with 33's with my 5:29 gears than I did with stock 4:10's.
FWIW-- I get much better mileage with my 87 4runner lifted with 33's with my 5:29 gears than I did with stock 4:10's.
BlackWorksInc
New member
That's entirely possible, but the 2UZ-FE in stock flavoring seems to handle weight pretty well. The GX470 is running the same drivetrain as the V8 4Runners, so while a bit more sluggish than stock; I doubt it's enough to drop it in the single digits.
MrRoo
New member
Lets use the KISS rule on this one. If you have over a 100,000 miles, you should do yourself a favor and replace the front bank O2 sensors. Very common on any car to have these cause bad MPG. Ive been a tech for 15 years as a profession. Seen them cause issues way too much. Get a handheld OBD scanner and watch your AFR numbers. Should be right at 14.7ish while cruising. But the major thing is your not calculating the correct mileage to begin with. Big tires and stock gears with no ECU change is killing your numbers. Use GPS mileage and see what the "real" numbers are. My 3rd gens averaged 16 in the city and my current V8 4runner is right at 15 in the city with winter fuel.
bob3dsf
New member
Smelling natural gas?!
Ummmm, not to high jack or anything, but if you are smelling natural gas in your garage, you ought to look for a pilot light out, if all pilot lights are ok then call someone to check your gas fed appliances. If it's not you and, as you say, the adjacent unit is vacant, call the realtor as a courtesy but you should get the fire dept. there. If the condo/apt/townhouse closed up and you are smelling natural gas that could turn into a major issue quickly. Ask me how I know.....
Ummmm, not to high jack or anything, but if you are smelling natural gas in your garage, you ought to look for a pilot light out, if all pilot lights are ok then call someone to check your gas fed appliances. If it's not you and, as you say, the adjacent unit is vacant, call the realtor as a courtesy but you should get the fire dept. there. If the condo/apt/townhouse closed up and you are smelling natural gas that could turn into a major issue quickly. Ask me how I know.....
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Well, pretend you have a brand new jeep rubicon. If you put 35" tires on it with stock gearing, you get exactly 9 mpg. Guess how I know that? part of the problem is the wind resistance from the truck being 10" higher and the other problem is that the rolling resistance from the tires is equivalent to towing 2000lbs all the time.
If you were bored, you could go here The Effects of Rotational Inertia on Automotive Acceleration and calculate the amount of equivalent weight that you have with your current setup (minus coefficient of drag losses), but I have done most of it for you: With 35" tires, that is equivalent to always having 800lbs or more in your truck. Now couple that with a drag coefficient of less than stock due to the lift (this number is debatable) but you now have the engine pulling against the force of no LESS than 1800lbs at 70mph. Then, add people and gear and suddenly you have 2500lbs+ all the time. I fail to see how this much weight can be negligible for gas mileage purposes.
