1999 tahoe 0411 swap gauge issues

[chevyracer8262]

I did an 0411 swap running the 02 express van 5.7 4l80e calibration on my 99 tahoe 383 4l80e conversio and now the speedo pegs at 100mph sitting at idle in park but when I drive it vcm scanner reads the correct speed also the tach is kinda all over the place sometimes it reads low sometimes it reads high any ideas what could cause this? It drives and shifts perfectly so I don't think it's a wiring problem