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Discussion Starter #1
Hey guys and gals,

Just wondering if any of you have one of the new GM 5.3L vortec pickups? I traded a few months back from a 2000 5.3L to a 2004 5.3L vortec. My old truck got about 16MPG around town and 18.5-19.5MPG on the hghway, but my new truck is not getting close to that. Last tank was 13.5MPG with a mix of around town and one 50 mile road trip. On straight highway it is getting 16.5MPG on a good day.

I thought that it might get a little better after the ECU did some learning and self tuning and the drive trane ran in for a couple thousand miles. It has almost 15k on it now and mileage is stick sucking hind ***.

The only thing that I can think would cause a problem like that would be an O2 sensor with an inaccurate crossover voltage causing idle and cruise to run richer than it should. I am thinking about making the dealership take a look at it, but I need some ammo. Anybody have any ideas?

Chris
 

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The AMC, FORD, & CHEVY Guy??!!
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Any difference between the two trucks? Like is one a 4x4 or an extended cab? Gear ratios steeper? An extended cab with steeper gears is obviously going to use more gas(not trying to make you sound stupid).

That sucks big time. I've got a 2004 F-150 4.2L w/ 5sp and get 19mpg on the freeway and 16mpg around town.
 

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Discussion Starter #3
Nope, the trucks are both extended cab with 3.42 rear gears. Basically the same exact truck 4 years newer.

Chris
 

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Turbo, I think you have the ammo now. First is the record you had on the previous truck, which sounds in line with what a couple of friends of mine experience. Second, the EPA ratings on the window sticker. The truck should fall in line with those unless it is a 2500, which may or may not had one. A search on JD Powers and Associates may give you some ammo also. Last, you want to start identifying a potential problem so you can come up with the data to exercise your "Lemon Law" options if it comes to that. One Bud has a 98 2500 that he special ordered and it has 4 wheel drive and gets near 18 mpg on a trip. He kept a log of his gripes and took it in for warranty work when he had enough to make it worth his time to take it in. When he left the dealer ship, he would log their fixes and carry over anything they failed to repair until his next visit. The dealer ship would take extra precautions to ensure any repeat gripes were taken care of because of the lemon law. When a dealership learns that you are keeping immaculate records of dates, times, and repairs, they take on an entirely different attitude toward trouble shooting and fixing your under warranty vehicle.
 

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Discussion Starter #7
Thanks for the info trees, I will have to make it clear that I keep records.

GJ, my window stickers says the truck should get 16/19 city/hwy mileage, so it is not even close to the sticker.

Later,

Chris
 

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Hey Chris,


If it gets to the point where you are looking at getting GM to take the truck back let me know. I have a few pointers from when I dealt with them. You want to get your problem documented before you put much more mileage on the clock. (if they buy it back they will ding you for the miles before the problem, it used to be .08 a mile)

Oh and my 1998 2500 4x with the 454 gets about 15-16 hwy, so somethings not cool.


John
 

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Discussion Starter #9
I am going to see how it does and go from there. They told me that since I modified the exhaust, airfilter, and put 18 inch wheels on the truck that it would likely get worse mileage.......which is bull#*$&!!

I talked to another dealership about it and the guy told me his truck is almost identical to mine and is doing the same thing. He said he was not happy about it either, but that it is not a warranty item.

I guess I dont understand what the window sticker mileage is all about. Does anyone know if there is some recourse if the vehicle does not get the mileage advertised? Or, are we just stuck to not like it?

Chris
 
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