Weird electrical pull at 75mph

[leukloki]

SO my mom got herself a 98 discovery. She really loves it, but its got some problems.
Im used to working on my little ford escorts, so for me this is a new challenge. I did search, but came up with nill so im posting to ask a few questions.

1. When she hits 75 mph the engine surges forward, (you can see it go up about 1000+ on the tac from where you are) And then after ward she can no longer seem to get the car to rev or speed up. it just continues to speed up.
2. got the check engine light looked at they said it COULD be the alternator...or something else. (they didnt specify what else it could be) The only alternator ive ever replaced was on a 98 eagle talon, and that one fried the battery, having the gate stuck open. Very different.
3. I have heard that it could be the battery. One of the cells could be dead and causing it to over charge? I dont know.
OR it could be the serpentine belt on the alternator?


If any one has any ideas, or maybe an extra alternator lying around that wont cost my ma 200 bucks, (cause she just spent a ton on this discovery) Please give me a pm or a call. I can answer any questions u have, but her car is in NJ and im in PA. So i cant run out and try stuff and come back and report. ANY way, thanks for any help!
610 883 6325. -Jackie

[Disco Mike]

Any fault codes, if you don't have them, get the 4 digit fault code numbers and get back to us.
It is not an alternator issue, most likely the XYZ switch on the tranny is starting to fail.

[mbrummal]

Originally Posted by Disco Mike

Any fault codes, if you don't have them, get the 4 digit fault code numbers and get back to us.
It is not an alternator issue, most likely the XYZ switch on the tranny is starting to fail.

98 D1. Mechanical transmission, there isn't an XYZ switch.