2 Problems with Taurus/Sable that need help

I'm new to this site so bear with me. My first problem is that on my 98 Mercury Sable my check engine light recently came on. I ran my ODB II reader
and it said it had that the speed sensor was malfunctioning. I was reading some other posts about speed sensors and a lot of the time it was something other than the sensor itself so I am beginning to doubt. The car also starts having symptoms other than what I would expect with a faulty sensor. When I go over about 60, the speedometer goes to zero. Shortly after that, the overdrive on/off light starts blinking. Around that time, my power steering also goes. And when I drive at slow speeds, it feels as if it were about to stall, as if it was a manual transmission. A couple times, if I drive around a lot, it acts as if the transmission is starting to go. If anyone has any ideas on that, please let me know. I'm a newbie at this kind of stuff.
Problem #2:
Last year, when I had to change the engine on my 97 Ford Taurus, I picked up an engine at a salvage yard. After putting it in, I found out that they had sold me a blown engine. So I brought it back and they readily gave me another one. I put that engine in, and everything works fine, the only problem now is that the check engine light doesn't turn off, and hence, it can't pass inspection. I ran the ODB test and it just says the code for engine compartment (or something along those lines). I brought it to a shop and they said they couldn't find a thing wrong with it at all. I'm wondering if the salvage yard possibly gave me, say, a '96 engine that my '97 computer doesn't fully recognize and therefore shows an error for it. I was wondering if there is any way to tell what year an engine is (whether it is the correct one or not) or if there is any other ideas that might be the cause of the problem. Thanks.
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RawPhenomenon wrote:

Need more detail on this, like for instance the actual code it's throwing. Offhand, ISTR that Sable has a hood-open detector switch (for under-hood lighting) and Taurus doesn't, maybe this is important - though I can't imagine why it would be.
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I don't know the code that came up for the Taurus. What happened was that it was overdue for inspection so I brought it to a shop (a couple months ago) and they said that they'd look at it to try to figure why the check engine light wouldn't go off. Two months later they got back to me and said they couldn't find out why it wouldn't work. The car runs fine and everything. I was just wondering if there was a correlation between changing the engine, and possibly putting a 96 Taurus engine in a 97 Taurus. The reason I suspect this is because the salvage yard we got it from didn't appear to be of the most honorable people, as they had already sold me a blown engine so I wouldn't put it past them to sell me an engine that didnt directly match.
Now, the problem with the Sable is all weird. The check engine light came on and the code said it was a problem with the speed sensor needing to be replaced, P0500 I assume (I had AutoZone do it for me because I left my reader at school). The thing that makes me think its not the speed sensor is that the power steering fails to work afterwards and then the car feels like its going to stall. Sorry for not having more descript information.
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you've got variable assist power steering, it uses the speed sensor signal, the slower you go the more ps assist and visa versa, as does the trans, and speedometer. the pcm and the gem modules also have speed sensor inputs. the sensor is at best difficult to get to. and sometimes it's the gear in the trans that's geared to the shaft that's geared to the sensor, that's stripped. Then the trans has to be removed for repair. and if you don't have a hoist and this is just for the sensor replacement I'd go to a Ford dealer. you have to drop the exhaust y pipe going from the front manifold to the rear. just to get your hand on the sensor and it's still a female dog to get the 10mm head bolt out. there's a 3x4 in heat shield that snaps on to the sensor if that's gone or you don't put it back on it will melt the wiring and the sensor. I would visually check the wiring to the sensor first. if you want pictures or wiring diagrams email me . roberttmcfadden[AT]hotmail[DOT]com
RawPhenomenon wrote:

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On Thu, 06 Jul 2006 21:07:46 GMT, "RawPhenomenon via CarKB.com"

The check engine light was coming on and I found that LOW BRAKE FLUID LEVEL tripped that sensor. I filled the container had have had no light since. The dealer did not know of that fix.
Jerry
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you've got variable assist power steering, it uses the speed sensor signal, the slower you go the more ps assist and visa versa, as does the trans, and speedometer. the pcm and the gem modules also have speed sensor inputs. the sensor is at best difficult to get to. and sometimes it's the gear in the trans that's geared to the shaft that's geared to the sensor, that's stripped.
Then the trans has to be removed for repair. and if you don't have a hoist and this is just for the sensor replacement I'd go to a Ford dealer. you have to drop the exhaust y pipe going from the front manifold to the rear. just to get your hand on the sensor and it's still a female dog to get the 10mm head bolt out. there's a 3x4 in heat shield that snaps on to the sensor if that's gone or you don't put it back on it will melt the wiring and the sensor. I would visually check the wiring to the sensor first. if you want pictures or wiring diagrams email me . roberttmcfadden[AT]hotmail[DOT]com
RawPhenomenon wrote:

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