WHEN I DRIVE MY CAR FAST MY SPEEDOMITER STARTS TO JUMP AROUND

What is your question?

WHEN I DRIVE AT FAST SPEEDS MY SPEEDOMETER STARTS TO JUMP AROUND I REPLACED THE VSS SENSOR BUT IT STILL HAS THE ISSUE?? IT WAS AN AUTOMATIC BUT WAS REPLACED WITH A FULL 6 SPEED CONVERSIAN ANY THOUGHTS?? THANKS

What makes this problem better or worse?

WHEN I DRIVE AT LOW SPEEDS IT WORKS

How long has your 1998 Toyota Supra had this problem?

RIGHT AFTER I DID THE 6 SPEED CONVERSION