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Fuel Mileage dropped after recall Throttle Body replacement

bcarlton0158

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bcarlton0158 Enthusiast

bcarlton0158

Posted
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I was getting 21 mpg on my first two trips to New Orleans from Bham. Took the truck in for the throttle body recall that required replacement and re flash of computer.. Now I am getting 16.5mpg

 

During this service visit I did have them level the front end.. I expected a slight loss, but not this..

 

Has anyone else had this recall performed? Issues?

newdude Senior Enthusiast

newdude

Posted
Posted

Perhaps when the throttle body procedure was performed something was re-programmed and wiped out the vehicles prior knowledge on how you were driving?

nvrnuf4me Enthusiast

nvrnuf4me

Posted
Posted

Took the truck in for the throttle body recall that required replacement and re flash of computer...

 

Throttle body recall?

I tried to search this and could not find anything about it. Would you mind telling me more about it?

Took the truck in for the throttle body recall that required replacement and re flash of computer...

 

Throttle body recall?

I tried to search this and could not find anything about it. Would you mind telling me more about it?

bcarlton0158 Enthusiast

bcarlton0158

Posted
  • Author
Posted

So all I know is the dealership told me about a week after purchase that this recall needed to be performed.. I bought the truck in September 2013. That is the extent of my knowledge..

 

Feel free to email Doug at Victory GMC in Calera, Al for more info. [email protected]

bcarlton0158 Enthusiast

bcarlton0158

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I put a Toyo AT on. It is the same width and a little less than 2" taller.. Not sure they weigh much more than factory... Kept factory wheels. I had an F150 w KMC XD wheels and Mickey Thompson ATZ.. Now they weighed a ton more than the factories... When I installed them, I was like WOW..

I put a Toyo AT on. It is the same width and a little less than 2" taller.. Not sure they weigh much more than factory... Kept factory wheels. I had an F150 w KMC XD wheels and Mickey Thompson ATZ.. Now they weighed a ton more than the factories... When I installed them, I was like WOW..

bcarlton0158 Enthusiast

bcarlton0158

Posted
  • Author
Posted

Also checked the mileage w the truck and w GPS.. Was less than .5 mpg different.

TxTruckMan Senior Enthusiast

TxTruckMan

Posted
Posted

It's your lift and tires, not the recall. Lift increases drag on the highway. Larger tires make your mileage wrong (need to reprogram to get correct) and the added weight will significantly decrease mileage as your engine has to turn exponentially more mass to get/keep you moving.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

2" taller, that means your odometer is showing less miles than you are actually traveling. Less miles on the tripometer means your calculations will be off.

fondupot Senior Enthusiast

fondupot

Posted
Posted

I put a Toyo AT on. It is the same width and a little less than 2" taller.. Not sure they weigh much more than factory... Kept factory wheels. I had an F150 w KMC XD wheels and Mickey Thompson ATZ.. Now they weighed a ton more than the factories... When I installed them, I was like WOW..

 

 

That's ur problem boss. Now your speedo isn't calibrating correctly and the AT tire is definitely heavier and has more rolling mass to turn compared to the OEM tires. So you probably arent getting as bad MPG as the computer is saying, you are actually driving further than what is being recorded.

 

Plus now with the lift, you aren't as aerodynamic before and you are punching a bigger hole through the air when driving. So you will be using more gas.

 

Always check ur mpg manually by taking miles driven on the tank and dividing by the gallons of gas you put in at a fill up. And now that your speedo calibration is off, the odometer reading is off as well. So figure out the size difference in the stock vs your new tires then take the miles on your tank and multiply by the % difference. That will tell you the true number of miles driven.

 

 

Or easy fix is to get a handheld and have the speedo re-calibrated. Some dealers will do it for you, but its hit or miss.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

There is nothing the dealers can re-calibrate for a tire size change. GM does not use a tire size in the calibration, they use rolling circumference and tire height. That is why when you look at the 3 different tires sizes GM offers on the trucks now they all have the same effective tire height. One calibration covers all of the possible tire sizes now from the manufacture.

8thsense Enthusiast

8thsense

Posted
Posted

My MPG seemed to get worse and truck had more hessitation after the re-flash but then again , it must be gas or weather related. I used HP tuner to read my stock tune file ECU/TCU before taking thew truck in and HP tuner will show line by line any changes to the ECU/TCU and nothing showed up. To get huge drops in MPG, it would have to go into DOD lesss, as that makes the largest difference in mpg on hwy.

 

I don`t know what the dealer changed but it does not show up in the ECU/TCU maps. Fuel/timing, trans and even dod show no changes. The dealer can flash into other areas of the system but HP tuner would show fuel, trans, timing and DOD changes. It even would show driver demand changes.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

I use HPT as well, only thing is if the tuning changes GM made are not in areas the HPT access then you wouldn't see them. I thought the only change though was fueling for remote start idle.

mzodarg Senior Enthusiast

mzodarg

Posted
Posted

It's been asked several times in this thread "What Throttle Body recall" First I've heard of it.

 

Mike

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