Tach reading issue

[dazza]

Something is up with my tach and I'm not sure what. It seems to be ok except when in third, it shows very high, right around 4500 when it's time to shift to 4th. Engine is sounding normal at this point, definitely not close to what the tach is showing. This reading is consistent in that it happens whenever in third.

Also, the other day at idle, I noticed it was showing around 3000, revving it moved the needle up but it didn't make it drop back to normal. Glanced at my phone for a few seconds and when I looked back up it had dropped to normal.

I was thinking maybe sticking at or near the needle but the consistent third gear reading shoots that theory down. Any ideas?