1997 Mercury Sable Jolts forward under 10mph

1997 MERCURY SABLE
79,000 MILES • 6 CYL • FWD • AUTOMATIC
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DREAMBORN
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My 1997 Mercury Sable will jolt forward under 10mph only if I'm going downhill. It won't do it if I'm applying gas or brake, only if I let it coast and it does it consistently. It won't do it at any other speeds, or uphill. Please help!

Check engine light is not on.
Apr 20, 2009 at 9:58 AM
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JGAROFALO
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[quote:63f7ad1c00="Dreamborn"]Shakes or Wobbles problem
1997 Mercury Sable 6 cyl Front Wheel Drive Automatic 79000 miles

My 1997 Mercury Sable will jolt forward under 10mph only if I'm going downhill. It won't do it if I'm applying gas or brake, only if I let it coast and it does it consistently. It won't do it at any other speeds, or uphill. Please help!

Check engine light is not on.[/quote:63f7ad1c00]

The PCM is trying to shift into 2nd, but the speed is right on the edge of the programming, and it is most likely hunting between 1st and 2nd gears.
Apr 20, 2009 at 5:42 PM
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DREAMBORN
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Powertrain Control Module?

Is there anyway to make certain of this? It's a $200 part.
Apr 21, 2009 at 7:07 AM
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JGAROFALO
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[quote:8b9e312271="Dreamborn"]Powertrain Control Module?

Is there anyway to make certain of this? It's a $200 part.[/quote:8b9e312271]

Replacing the part would not cure the problem necessarily. It would be a matter of programming. This may be just a small "bug" in the original programming of the PCM.
Apr 21, 2009 at 2:11 PM
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DREAMBORN
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Ok. I want to cringe when I think about bringing it to a Ford/Mercury Dealer scares me. But I will have it looked into. Thank you
Apr 21, 2009 at 3:09 PM