Crazy cutlass problems

[gmpower6]

Friend of mine has a 92 cutty with 3100. Here is the problem the darn speedo is bouncing all over the place and the car cuts out at that time. What would cause the speedo to do that?

Now it does not do it all the time and put a new tps on the car also. We are going to try a new ecm but need a few more idea's

Thanks Sean

 

[gmpower6]

ttt

 

[ThikStik]

VSS (vehicl speed sensor) also may be seeing same nutty speeds as sp ometer thus throwing motor off. Is there a cable drive on this car, if so check speeedo drive gears/cable. Or not if car gets electronic signal and speedo is digital.