That is over the limit of the Weber ECU micro processor speed.
(i assume you have a L8 or P8 as you have a PECTEL monitor on your dash)
I am surprised it runs reliably at that speed if at all!

The other guages/ignition lights do not tie up with this !!!

Perhaps the defi has been set up incorrectly and you are pulling our legs Dingy !

Please correct me if I am wrong..........