Motor races when rolling in neutral: 92 Dakota

Sorry to keep bothering this group with my questions, but I'm very new to owning a Dodge. My friend traded me his '92 Dodge Dakota for my '71 Husky dirt bike (bike runs, only has 3200 original miles on it) last week.
What I've noticed with the Dakota (2.5L 4 banger, five speed, TFI, 2WD) is that although it runs all right otherwise, it does two strange things:
1. When you first start the motor, it races for a few seconds and then slows down to a normal idle. This may be a normal choke sequence, I don't know, but:
2. As soon as the truck starts moving in a forward direction (either coasting in neutral OR in gear- doesn't matter) the motor starts racing a bit again and won't stop doing it until I come to a complete stop. It doesn't do this when rolling in reverse. To my way of thinking, this sounds like some kind of sensor problem like maybe the vehicle speed sensor on the tranny, but who knows?
My friend said that it hasn't always done item 2.
Does anybody have any idea why this is happening?
TIA
--
John Corliss

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Check the motor mounts?
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Tom Lawrence wrote:

No I didn't, and I'm afraid I'll have to wait a while to do it since we're buried in snow here.
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John Corliss

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John Corliss wrote:

Well, it's snowing again, but I think I'll get in the truck and see what computer error codes are loaded, if any (you turn the key on-off-on-off-on within two seconds and watch the light on the dash flash.)
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John Corliss wrote:

Check the motor mounts. AS Tom said.
JAM
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Why???
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TBone wrote:

The truck is 16 years old. It's not unreasonable that a motor mount has broken.
If a motor mount is broken the motor will rise up on the side that is broken, the throttle cable tightens and the motor races.
I've seen this twice in the old Dodges and Plymouths I have owned.
JAM
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While not unreasonable, I would also think unlikely but worth a look just the same.

That is not always true and depends on which motor mount is broken. I can't speak for your vehicles, but the cable in my 97 Ram is more than long enough to deal with the movement from a broken motor mount and if the engine is really moving that much, it should also cause problems with the trans linkage. The OP also said that this condition occurs whenever the vehicle is moving both in and out of gear so what would cause the engine to lift at idle under motion and not when sitting still? This is why I am curious about this. If it only occured while moving and in gear then this is a much greater possibility but if it also does it in neutral, then it is either not the problem or he also has other problems besides a broken motor mount.
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At one time GM had such a problem with engine mounts which caused sudden acceleration, they did a recall and had a cable installed to stop the engine lift.
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Roy wrote:

I kind of thought that was where you were going with this, the motor pulling on the throttle cable, but you have to remember that the racing occurs when the truck is in neutral and coasting. Also, I have my foot off of the pedal.
My feeling is that this is some kind of a sensor problem. Throttle fuel injection is pretty complex, and once I get the error codes out of the computer (maybe tomorrow) I'll post them here and we'll have a better idea of what's going on.
Thanks very much for your input though!
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TBone wrote:

I should have mentioned that the motor was rebuilt by the dealership (under warrenty) only 80k miles ago. I don't think either they or my friend would allow a broken motor mount to go unrepaired. 80)>
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The driver's side mount keeps the engine from lifting. The passenger side mount is under compression.
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Ken



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Bill Dukenfield wrote:

I'll do it, but as TBone asks and out of curiosity... why?
Should have done it the day before yesterday since there was actually a sucker hole in the sky right over my place.
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Ok, now you have me curious. With the conditions that he described, what do the motor mounts have to do with it?
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