All I can say is WOW. I tried to look thru a manual for a solution and found none. We need a code to diagnose the problem as has already been stated.
As a rooky I have posted what I might do in this situation. Good luck
Were speedometer self diagnostics done to check for codes ?
CHECK ENGINE LAMP
When the lamp turns off after being illuminated for the first four-second period, it will:
a. remain off if there are no fault conditions or trouble codes currently detected by the Ignition Control Module.
b. come back on for an 8-second period if only historic codes exist.
c. come back on, and remain on, if a current trouble code exists.
NOTE:
Some DTCs can only be fully diagnosed during actuation. For
example, a problem with the ignition coil will be considered a
current fault even after the problem is corrected, since the ECM
will not know of its resolution until after the coil is exercised by
vehicle start sequence. In this manner, there may sometimes
be a false indication of the current trouble code
The engine management system provides two levels of diagnostics.
• The most sophisticated mode employs a computer-based diagnostic package called DIGITAL TECHNICIAN (Part No. HD-44750).
• The second mode requires using the speedometer self diagnostics. Speedometer, ABS, tachometer (if equipped), TSM/TSSM/HFSM and ECM DTCs can be accessed and cleared
Diagnostic Tips
• For a quick check of speedometer function, a "WOW" test can be performed. Press and hold trip odometer reset switch then turn Ignition Switch to IGNITION. Background lighting should illuminate, speedometer needle should sweep its full range of motion, and indicator lamps (sixth
gear, check engine, low fuel, battery, security, cruise enabled, pursuit, and ABS) should illuminate. Some lamps, like the cruise enabled lamp, may illuminate even if the vehicle is not equipped with cruise control. See Figure 4-8.
• If speedometer fails "WOW" test, check for battery, ground, ignition, trip odometer reset switch and accessory wiring to speedometer. If any feature in the speedometer is nonfunctional.
DIAGNOSTICS NOTES
Each reference number below correlates to a circled number on the flow chart.
1. To exit diagnostic mode, turn Ignition Switch OFF.
2. To clear DTCs for the selected module:
a. Press and hold the trip odometer reset switch for more than 5 seconds to display available modules, release.
b. Press the trip odometer reset switch to choose module.
c. Press and hold the trip odometer reset switch for more than 5 seconds to display the DTC, release.
d. Press and hold the trip odometer reset switch for more than 5 seconds to clear DTC(s) for the module selected.