My 05 V8 4x4 has consistently got 17-18 MPG . I have just over 90000 miles and in the last week or 2 have noticed my mileage averaging around 14-15 MPG. That's all based on the onboard computer. Haven't checked it manually yet. I haven't done anything to it before this change, except increase my tire pressure from 32-35 psi. My mechanic checked the plugs not long ago and said they looked ok, nevertheless, I haven't had it "tuned up". Just wondering what might cause such a sudden drop like this...if there's something in the maintenance schedule that could be the cause.
Sudden drop in mileage
- Thread starter Cumby
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Might want to calculate manually, changes in tire pressure will affect MPG. I know a lot of members don't rely on the digital reading offered by the 4runner. Maybe your driving habits have changed? I know I used to be a much more reserved driver but got a little more aggressive on the pedal after installing an exhaust because I like hearing the V8. So i know that contributed to my own drop in MPG
wnelax04sr5
New member
potential explanation could be a bad sensor, MAF or O2, sending a bad reading and either leaning out the AFR or making it too rich, causing economy to suffer
Minn3sota
New member
There are a multitude of ways in which a decrease in a few MPG could be explained. The ones mentioned above are great starting points. I've found fuel octane rating to have a significant impact on MPG. Have you switched octane rating, or filled up at a new gas station? Most people would agree there is a difference in winter and summer fuel with relation to MPG. Possibly there was a switch over in your area.
A safe increase in tire pressure should increase gas mileage slightly. Less rolling resistance would equal less fuel input.
Gas Mileage Tips - Keeping Your Vehicle in Shape
A safe increase in tire pressure should increase gas mileage slightly. Less rolling resistance would equal less fuel input.
Gas Mileage Tips - Keeping Your Vehicle in Shape
RL Lemke
New member
To reset the computer disconnect the battery for 15 minutes, or so. Otherwise it takes as many as 50 engine restarts for the change in fuel to be accommodated.
Whether there is as much energy in one blend or another is a different matter. Ethanol produces less energy than real gasoline.
Whether there is as much energy in one blend or another is a different matter. Ethanol produces less energy than real gasoline.
chitown40
Member
Winter gas will explain the 2-3 MPG drop. Also, check for a stuck brake caliper and the other fuel/air system items mentioned above.
And.... figure out your mileage by hand. I can make the on-board dream-o-meter computer spit out any number I want based upon my driving habits, idle time, etc. None of it is accurate. A simple hand calculation based upon miles driven divided by gallons used will give you a true real life number.
And.... figure out your mileage by hand. I can make the on-board dream-o-meter computer spit out any number I want based upon my driving habits, idle time, etc. None of it is accurate. A simple hand calculation based upon miles driven divided by gallons used will give you a true real life number.
