My 01 V6 does that too, but it only happens rarely. I figured it was probably a loose connection somewhere going to the cluster. If I shut it off and back on again, the display comes right back. Then it will go months before it happens again. Since its only happened a few times, it seems like more trouble than it's worth to try and fix yet.
2001 Zinc Yellow V6 3.8L Coupe
65mm TB & Spacer, K&N FIPK CAI, Trac-loc, 4:10 Gears, Custom tune from Pro-Dyno, LT Headers, H-Pipe, High-flow Cats, Flowmaster 40's, UD pulley's, Upper and lower rear control arms, Drag launch springs, Line-locks, Custom Built 4R70W Trans,2500 RPM Torque Converter, Trans Cooler, 190 LPH fuel pump