Speedo and Tach Not working WHY??

electronic speedo and tach in my 90 Grand prix LE 3.1L (not digi) my rpm guage maxed out over max when i turned car off and stuck there and then the speedo doesn't move at all, i hit the dash to make the rpm guage go back to 0, i hooked up a comp to it and ran a data stream test , and found that the idle rpms are at 150 and when u rev it, she drops to 25 rpm (impossible) :banghead:
the crank rpms reads 5 rpm idle and when u rev it she reads 1:banghead:
but the speedo in the computer says it is working properly, but does not show on the CLUSTER.:screwy:
i have alrdy checked the ECM for voltage from the speed sensor and going to cluster and also checked connectivity, and i have a signal at the DIS, and was ok
PLEASE PLEASE HELP ME