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I have a 1999 Dodge Dakota. It is a V6, 3.9 Liter, auto transmission. I have a weird problem that no one has been able to answer for me.

HOW I CAME TO REALIZE THE PROBLEM:

One day I was driving home and had to stop at a stop light. The light turned green and I took off. For some reason it would not shift out of 1st gear at all. So, I was stuck driving at 3000 RPMs and 25ish MPH. I drove to a bank and parked it. The next day I went to get it. I was just going to drive it home and figure out what was wrong with it later. It was still acting the way it did the night before, not shifting. I noticed I didn't have enough gas to get home to I stopped at the gas station and filled it up. When I pulled out of the gas station it started shifting normally again.

So, I have had this happen to me a few times now. It is always when I am really low on gas. Once I fill it up with gas the problem goes away. It usually occurs around an 1/8 of a tank. Why is this happening? How does the level of gas in the tank have anything to do with it shifting?

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How low is this? I have seen auto manufacturers wire up some odd stuff in the electronics to ensure the owner's do something, but this is certainly odd - like an unknown bug! –  jp2code Oct 13 '12 at 1:36
    
You think this was intentional from the manufacturer? I have never heard of anyone else having this problem. –  Linger Oct 14 '12 at 2:02
    
I doubt it. But, I spend a lot of time on the Nissan Hardbody forum, and Nissan has coded in some strange behaviors whenever it gets bad readings from sensors. It could be that you have water in the bottom of the tank. –  jp2code Oct 14 '12 at 15:57
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limiting the rev range and gears is a fairly common "limp-home" mode in many modern case. As Jp2code suggests, it is probably pickingup some sort of error from one of the sensors somewhere. –  Nick C Oct 15 '12 at 13:08
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Limiting the user to one gear when it is critical they efficiently reach a gas station seems like a liability... –  Eric Fossum Nov 5 '12 at 4:19

1 Answer 1

Maybe when the tank is low you are effecting the vacuum on the engine. Many cars rely on the vacuum to tell the transmission when to shift.

Anyone have thoughts on this idea?

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