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My '04 v6 4x4 5speed is getting a dismal 14mpg. I just bought it with 38K on it. I know - this subject has been worn to frazzles, but one of the suggestions I've read is unplugging the battery to reset the ECU. First - does that work with the older v6 like mine or only with the vvti engines?
And second, has resetting the ecu ever actually improved anyones mileage?
This isn't meant to be argumenative - I really want to know if it's worked!! :tu: :ts:
 

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I tried the computer reset by unhooking the battery and I did see a small improvement in my city mileage, only about 1 MPG but my highway mileage remained unchanged. It's worth a try as the computer is said to learn your driving habits, I'm thinking about trying it again on my next major highway trip to see if it will improve the highway mileage.:)
 

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On my 2002, I've had the battery disconnected twice for various reasons, including a battery replacement. In regards to changes in MPG, neither disconnection resulted in any change. My mileage always seems to be 14mpg around Boston, and 19-20 mpg when on the road, 60-65mph average. The road mileage seems to stay the same, even with a large kayak on the roof.
 

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It's true the ecu will learn driving patterns (to an extent) but it probably will not vastly improve fuel economy. Get new spark plugs, fuel filter, and make sure you have the right tire pressure and a good alignment. Don't have a lead foot, and you should notice somewhat of an increase in mpg.
 

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It is amazing whta happens when ya drive 60-65 vs 70 -75MPH or even faster!! ya gotta keep the RPM's below or just at 2K to get any decent MPG and i know that it is hard to keep it below 65!! next to impossible but any decent maintenance manual will elaborate on this very issue and they have been for years. Ecu's supposedly have memory capability but i feel strongly that this meomry is not being used to better or worsen MPG!! i feel it is storing your driving patterns pure and simply to benefit toyota in some way??
 

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YES

I drive 120 miles to get home from school. If I drive 70-75 mph i will get 16.5-17.5 mpg where if I drive 60-65 mph I will get 17-18 mpg. This past weekend I read about reseting the ecu and thought I would give it a try. Immediatly after reseting my ecu I filled up on gas and started driving. I drove 65-70 the whole way and floored it once or twice. I was shocked when I filled up at home. 18.98 mpg! That is the best I have ever got on this truck.
I can't say for sure but from the begining, after reseting ecu, it felt as though my truck ran different. Maybe a little rougher vibrations from motor as the rpms' climbed and no more hard shifts, much smoother gear changes. After racing a ford lightning and running around town, my truck has gone back to the hard shifting, smoother idleing truck its always been. Its probably just in my head but I will keep playing around with it until I see a pattern.
 

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well so far I'm leaning towards "myth busted" but i'm gonna give it a little longer before I say for sure :)

since trying this I went through about 1/4 tank then filled it up again and now at 3/4 I have 74 miles on my odometer which is about where it always was before resetting the computer...

I will wait till my next full tank to confirm this because we also have had some pretty cold weather here and that never helped my mileage :)
 
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