When my 01 Grand Sport is not running the speedo sits at 9 mph. When running and not moving, my speedo needle goes crazy, flipping back and forth. When doing this, if I try to pull out of my driveway (in D or R) I get jerking out of the van, which then smooths out when I get going.

I have changed the in/output speed sensors with no change in behavior...however it did get rid of all of the trans codes that were indicative of speed sensor issues.

It was not until I was experiencing the speedo issue and jerking of the van, that it constantly showed 9 mph over.

Any ideas on what is causing this or what I can do to fix it all?

 

You are going to need to get access to a scan tool to see what is causing the issue. It could still be in the transmission, the PCM or the cluster. That is a tough problem to just guess at because it could be so many different things.

 

I agee as well.

 

I take it that you mean a snapon-type scanner, vs. the Autozone scanners...? Because it has been scanned by one of those.

 

You need to be able to read sensors while driving the vehicle to determine what is causing the speedo to malfunction.