Help !!!! VSS or something else

[o1roadkingrider]

My 91 Coupe Deville shifts erratically at lower speeds, below 45mph, and the speedometer goes nuts as well. The VSS was replaced three years ago but did not fix the problem, so the vehicle was parked.

When I first got the car and started driving it there was no problem with the shifting, speedometer or anything like that. Three weeks later it's beginning to act up on a consistent basis. I bought a new VSS to install but am concerned about throwing away $47.00 for nothing. If it isn't the VSS, what could cause this?

It seems to be related to throttle position, as when traveling under 45 and I gently apply throttle the speedometer goes to a zero or 15mph reading then the trans will start shifting up and down erratically.

Help!!!! Does anyone have any good input on this?

[o1roadkingrider]

Anyone have a VSS (vehicle speed sensor) go out that can share their experience? Someone supposedly already replaced this sensor on my car but it didn't fix it.

[Ranger]

Start by pulling the codes.

[o1roadkingrider]

O.K. I pulled the codes. Here's the list:

E24
E52
E64
E75
E98

I'm going to see if I can find out what they are. Any ideas?

[o1roadkingrider]

Found a good site for this data:

http://autorepair.about.com/cs/troub..._dtcs_main.htm

Here's what they are:

E24 speed sensor circuit problem
E52 PCM/ECM memory reset
E64 cruise-acceleration too high
E75 Intermittent VSS signal
E98 P/N to D/R ISC engaged problem

So... what do you think?

[Ranger]

Since the VSS has been replaced, I'd concentrate on E24. Check the connector and wiring for chaffing or brakes.

This is another good place to go for code definitions.
http://myweb.accessus.net/~090/dtcobd1.html