Speedometer and Rev Gauge

[Daner_Ranger]

First problem
My rev gauge as i call it lol when idle sits rite on zero but when i touch gas it will move up then sit back down to zero less I am driving.

I know there a post right at top for speedometer issues but doesnt cover my problem. I have a 2000 ford ranger. The speedometer doesnt flactuate or dont work until certain speed. I have the right size tires on my truck. It says my truck is reving at like 2,400rpm in 5th doin 150kph which I know aint right. I havent check what my gears are yet in the back since I just bought truck today but I will very soon.

 

[Daner_Ranger]

I am going to get a new speed sensor and see if that fixes my problems